JP5183533B2 - Method for producing transparent thermoplastic resin molded product - Google Patents

Description

The present invention relates to a method for producing a transparent thermoplastic resin composition transparent thermoplastic resin molded article using the electromagnetic wave irradiation molding.

In general, there are various molding methods such as injection molding, blow molding, extrusion molding, and press molding as methods for obtaining a resin molded product having a predetermined shape using a thermoplastic resin.
On the other hand, for example, in Patent Document 1, when a resin molded product made of a thermoplastic resin is molded by a vacuum casting method using a rubber mold, a thermoplastic resin is selected for the mold. A resin molding method that can be heated automatically is disclosed. In this resin molding method, when a molten thermoplastic resin is filled in a cavity of a mold, an electromagnetic wave including a wavelength region (near infrared region) of 0.78 to 2 μm is thermoplasticized through the mold. By irradiating the resin, the thermoplastic resin can be positively heated as compared with the rubber mold because of the difference in physical properties between the rubber constituting the mold and the thermoplastic resin.
Also, for example, in Patent Document 2, a powdered powder slush material is adhered and melted to a mold surface with a desired thickness, and then the material is cooled to form a resin molded product on the mold surface. A powder slush molding method is disclosed.

JP 2007-216447 A JP 2000-254930 A

  However, in the resin molding method of Patent Document 1, a thermoplastic resin having a color such as black is used in order to improve the absorption of electromagnetic waves including the near infrared region. For this reason, when a transparent (including translucent) thermoplastic resin is molded, further ingenuity is required.

The present invention has been made in view of such conventional problems, and is a transparent heat for electromagnetic wave irradiation molding capable of rapidly forming a thermoplastic resin molded article having a haze value of 20% or less by electromagnetic wave irradiation molding. it is intended to provide a method for producing a transparent thermoplastic resin molded article using the thermoplastic resin composition.

A first reference invention is a transparent thermoplastic resin that is filled in a cavity of a rubber mold made of a rubber material, and is heated and melted by irradiating an electromagnetic wave including a wavelength region of 0.78 to 2 μm through the rubber mold. A composition comprising:
It contains 0.0005 to 0.1 parts by mass of an infrared absorber with respect to 100 parts by mass of the transparent thermoplastic resin.
The transparent thermoplastic resin composition has a haze of 20% or less when formed into a transparent thermoplastic resin molded article .

The transparent thermoplastic resin composition of the present invention is a composition that exhibits an excellent effect in electromagnetic wave irradiation molding (a method in which a thermoplastic resin is irradiated with electromagnetic waves through a rubber mold for molding).
Specifically, the transparent thermoplastic resin composition of the present invention contains 0.0005 to 0.1 parts by mass of an infrared absorber with respect to 100 parts by mass of the transparent thermoplastic resin. And when filling this transparent thermoplastic resin composition in the cavity of a rubber mold and irradiating this transparent thermoplastic resin composition with an electromagnetic wave including a wavelength region of 0.78 to 2 μm through the rubber mold, An infrared absorber can effectively absorb electromagnetic waves.

Thereby, even if it uses a transparent thermoplastic resin as a thermoplastic resin, the said electromagnetic waves can be absorbed effectively and a transparent thermoplastic resin composition can be heated and melted rapidly. Therefore, by blending the infrared absorber, a transparent thermoplastic resin molded product having a haze value of 20% or less representing the transparency of the resin can be rapidly molded by electromagnetic wave irradiation molding.
In addition, it is easy to manufacture a rubber mold as a mold, and various shapes of transparent thermoplastic resin molded products can be molded at low cost.
In addition, the transparency of this invention includes a translucent thing.

The second reference invention is a transparent thermoplastic resin molded article produced by a method for producing a transparent thermoplastic resin molded article, and having a haze value of 20% or less .

The transparent thermoplastic resin molded article of the present invention is manufactured (molded) using the transparent thermoplastic resin composition described in the first invention.
Therefore, various shapes of transparent thermoplastic resin molded articles having a haze value of 20% or less can be quickly and inexpensively molded by electromagnetic wave irradiation molding.

3rd invention contains 0.0005-0.1 mass part of infrared absorbers with respect to 100 mass parts of transparent thermoplastic resins, and the haze value when it is set as a transparent thermoplastic resin molded article is 20 % And a number average particle diameter of 300 to 3000 μm , and a method for producing a transparent thermoplastic resin molded article using a particulate transparent thermoplastic resin composition,
An arrangement step of arranging the transparent thermoplastic resin composition in a cavity of a rubber mold made of a rubber material;
A heating step of irradiating the transparent thermoplastic resin composition in the cavity through the rubber mold with an electromagnetic wave containing a wavelength region of 0.78 to 2 μm to heat and melt the transparent thermoplastic resin composition; ,
In the manufacturing method of the transparent thermoplastic resin molded article which comprises a cooling step to obtain a transparent thermoplastic resin molded article is cooled the transparent thermoplastic resin composition of the molten state (claim 1).
Moreover, 4th invention contains 0.0005-0.1 mass part of infrared absorbers with respect to 100 mass parts of transparent thermoplastic resins, and the haze value when it is set as a transparent thermoplastic resin molded product Is 0.1 to 20% by mass of a small transparent thermoplastic resin particle having a particle diameter of 1 to 100 μm and the remainder being larger than the small transparent thermoplastic resin particle. A method for producing a transparent thermoplastic resin molded article using a transparent thermoplastic resin composition comprising large transparent thermoplastic resin particles,
An arrangement step of arranging the transparent thermoplastic resin composition in a cavity of a rubber mold made of a rubber material;
A heating step of irradiating the transparent thermoplastic resin composition in the cavity through the rubber mold with an electromagnetic wave containing a wavelength region of 0.78 to 2 μm to heat and melt the transparent thermoplastic resin composition; ,
A cooling step of cooling the molten transparent thermoplastic resin composition to obtain a transparent thermoplastic resin molded product, and a method for producing a transparent thermoplastic resin molded product.

In the method for producing a transparent thermoplastic resin molded article of the present invention, the transparent thermoplastic resin composition described in the first invention is used.
Specifically, first, as a placement step, a transparent thermoplastic resin composition is placed in a rubber mold cavity. The transparent thermoplastic resin composition can be filled in almost the entire cavity, or can be filled in a part of the cavity.

  Next, as a heating step, the transparent thermoplastic resin composition in the cavity is irradiated with an electromagnetic wave including a wavelength region of 0.78 to 2 μm through a rubber mold. At this time, the transparent thermoplastic resin composition can be selectively heated compared to the rubber mold due to the difference in physical properties between the rubber material constituting the rubber mold and the transparent thermoplastic resin composition (transparent thermoplastic resin). The amount of heating of the composition can be increased). Thereby, the temperature rise of a rubber type | mold can be suppressed and a transparent thermoplastic resin composition can be fuse | melted. In addition, since an infrared absorber is blended with a transparent thermoplastic resin, the above electromagnetic wave can be effectively absorbed even when a transparent thermoplastic resin is used as the thermoplastic resin, and the transparent thermoplastic resin composition Can be rapidly heated and melted.

Therefore, by blending the infrared absorber, a transparent thermoplastic resin molded product having a haze value representing the transparency of the resin of 20% or less can be rapidly molded by electromagnetic wave irradiation molding.
In addition, it is easy to manufacture a rubber mold as a mold, and various shapes of transparent thermoplastic resin molded products can be molded at low cost.

Explanatory drawing which shows the state which performed the arrangement | positioning process in the manufacturing method of a transparent thermoplastic resin molded product in an Example. In an Example, explanatory drawing which shows the state which performs the vacuum process and a heating process in the manufacturing method of a transparent thermoplastic resin molded product. Explanatory drawing which shows the state which performed the filling process in the manufacturing method of a transparent thermoplastic resin molded product in an Example. In an Example, the wavelength (nm) is taken on a horizontal axis and the light transmittance (%) is taken on the vertical axis | shaft, and the graph which shows the light transmittance about transparent silicone rubber and translucent silicone rubber. In the examples, the horizontal axis represents the wavelength (nm), the vertical axis represents the light absorption rate (%), and the thermoplastic resin containing no infrared absorber and the thermoplastic resin contained the infrared absorber. The graph which shows the light absorption rate (%) about a thermoplastic resin composition. In an Example, explanatory drawing which shows the state which fills the cavity of a rubber mold with small transparent thermoplastic resin particles and large thermoplastic resin particles. In an Example, explanatory drawing which shows the state which fills only the large transparent thermoplastic resin particle in the cavity of a rubber mold.

A preferred embodiment in the second to fourth inventions described above will be described.
In the second to fourth inventions, the reason why the transparent thermoplastic resin composition can be selectively heated by the electromagnetic wave including the wavelength region of 0.78 to 2 μm as compared with the rubber mold is as follows. Think like this.
That is, the electromagnetic wave including the wavelength region of 0.78 to 2 μm irradiated on the surface of the rubber mold is absorbed by the transparent thermoplastic resin composition through the rubber mold as compared with the ratio absorbed by the rubber mold. I think that the ratio is large. Therefore, it is considered that the energy of light due to electromagnetic waves including a wavelength region of 0.78 to 2 μm is preferentially absorbed by the transparent thermoplastic resin composition, and the transparent thermoplastic resin composition can be selectively heated.

Moreover, as an electromagnetic wave irradiated to the said transparent thermoplastic resin composition through the said rubber type | mold, not only the electromagnetic wave of the wavelength range whose wavelength is 0.78-2 micrometers, but the electromagnetic wave of the area | region other than this may be contained. Good. In this case, the electromagnetic wave or transmitted electromagnetic wave irradiated to the transparent thermoplastic resin composition via the rubber mold may contain more electromagnetic waves in the wavelength region having a wavelength of 0.78 to 2 μm than electromagnetic waves in other regions. preferable.
The reason for using an electromagnetic wave having a wavelength of 0.78 to 2 μm for heating the transparent thermoplastic resin composition is that the electromagnetic wave having a wavelength of this wavelength easily transmits through a rubber mold. This is because the plastic resin composition is easily absorbed.

The electromagnetic wave preferably has an intensity peak in a wavelength region of 0.78 to 2 μm. In this case, a halogen heater, an infrared lamp, or the like having a predetermined distribution characteristic for the wavelength of the emitted electromagnetic wave can be used as the electromagnetic wave generation source.
The rubber mold can be formed from a transparent or translucent silicone rubber as a rubber material. The hardness of this silicone rubber can be set to 25-80 in the JIS-A standard measurement.

  In the first to third inventions, the haze value is a value obtained in accordance with JIS K7136 using a test piece having a thickness of 2.5 mm. The haze value is closer to transparency as the value is smaller. When the transparent thermoplastic resin composition is a transparent thermoplastic resin molded article, the haze value is preferably 15% or less, more preferably 10% or less, and particularly preferably 8% or less. The lower limit value of the haze value can be set to a value close to 0% by reducing the blending amount of the infrared absorber.

  When the content of the infrared absorbent with respect to 100 parts by mass of the transparent thermoplastic resin is less than 0.0005 parts by mass, the amount of the infrared absorbent is too small, and the transparent thermoplastic resin composition has an effect of absorbing electromagnetic waves. It is not fully demonstrated. On the other hand, when the content of the infrared absorbent with respect to 100 parts by mass of the transparent thermoplastic resin is more than 0.1 parts by mass, the infrared absorbent is too much, and the haze value of the molded transparent thermoplastic resin molded product is reduced. It becomes difficult to keep it below 20%.

Further, as the infrared absorber, various agents that absorb electromagnetic waves including a near infrared wavelength region of 0.78 to 2 μm can be used.
As the infrared absorbent, either an inorganic infrared absorbent or an organic infrared absorbent can be used. The inorganic infrared absorber is at least one selected from the group consisting of metal oxides such as tin oxide, zinc oxide and copper oxide, antimony-doped tin oxide, indium-doped tin oxide, In, Ga, Al and Sb. Examples thereof include metal complex compounds such as zinc oxide containing elements.
Organic infrared absorbers include anthraquinone dyes, cyanine dyes, polymethine dyes, azomethine dyes, azo dyes, polyazo dyes, diimonium dyes, aminium dyes, phthalocyanine dyes, naphthalocyanine dyes, India Examples include cyanine dyes, naphthoquinone dyes, indolephenol dyes, triallylmethane dyes, metal complex dyes, dithiol nickel complex dyes, azocobalt complex dyes, squarylium dyes, and the like.

  The blending amount of the infrared absorber is preferably 0.001 to 0.08 parts by weight, more preferably 0.005 to 0.06 parts by weight, per 100 parts by weight of the thermoplastic resin. By setting the blending amount to 0.0005 parts by weight or more, it is possible to further shorten the time required for heating and melting the transparent thermoplastic resin composition by irradiating electromagnetic waves. One type of infrared absorber can be used, but two or more types can be used in combination.

As the transparent thermoplastic resin, various transparent materials (including translucent materials) may be used as long as the haze value described in JIS K7136 is 20% or less when the transparent thermoplastic resin is a molded product having a thickness of 2.5 mm. .) Can be used.
Specifically, the transparent thermoplastic resin includes polystyrene, AS resin, MS resin, styrene resin such as transparent ABS resin, acrylic resin, polycarbonate resin, polyester resin such as PET resin, PEN resin, and vinyl chloride resin. , Cycloolefin resin, polymethylpentene resin, polyarylate resin, and the like can be used. Among these, since it is excellent in moldability and impact resistance, it is preferable to use transparent ABS resin, acrylic resin, and polycarbonate resin.

The transparent thermoplastic resin is preferably amorphous (Claim 4 ).
The cooling rate of the transparent thermoplastic resin in the rubber mold is slower than that of the mold because the rubber mold is made of a rubber material. As a result, the crystallinity of the transparent thermoplastic resin may increase during cooling, which may reduce the dimensional accuracy of the transparent thermoplastic resin molded product or the impact resistance of the transparent thermoplastic resin molded product. There are things to do. On the other hand, by making the transparent thermoplastic resin amorphous, it is possible to prevent a decrease in dimensional accuracy and a decrease in impact resistance of the transparent thermoplastic resin molded product.

The transparent thermoplastic resin is a rubber-reinforced vinyl resin obtained by polymerizing a monomer component containing 50% by mass or more of a (meth) acrylic acid ester compound in the presence of a rubbery polymer, a rubber-reinforced vinyl-based resin, it is preferable to include a structural unit derived from a vinyl-based monomer (co) mixture obtained by mixing the polymer (claim 5).
In this case, a transparent thermoplastic resin molded product having a haze value of 20% or less can be easily obtained.

The transparent thermoplastic resin can be composed of a resin mainly composed of transparent ABS (acrylonitrile / butadiene / styrene) resin.
Examples of the (meth) acrylic acid ester compound used for the transparent ABS resin include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, and cyclohexyl. Acrylate esters such as acrylate, dodecyl acrylate, octadecyl acrylate, phenyl acrylate, benzyl acrylate, or methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, octyl methacrylate, 2 -Ethylhexyl methacrylate, cyclohexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, phenyl methacrylate DOO, and methacrylic acid esters such as benzyl methacrylate. Among these, methyl acrylate, butyl acrylate, and methyl methacrylate are preferable.

  The rubbery polymer used for the transparent ABS resin has a glass transition temperature (Tg) of −10 ° C. or less, and is a conjugate of polybutadiene, polyisoprene, butadiene / styrene copolymer, butadiene / acrylonitrile copolymer, and the like. Diene rubber, ethylene / propylene copolymer, ethylene / propylene / non-conjugated diene copolymer, ethylene / butene-1 copolymer, ethylene / butene-1 / non-conjugated diene copolymer and other olefin rubbers, acrylic Rubber, silicone rubber, polyurethane rubber, silicone / acrylic IPN rubber, natural rubber, conjugated diene block copolymer, hydrogenated conjugated diene block copolymer, and the like. Among the rubbery polymers, conjugated diene rubber, olefin rubber, and acrylic rubber are preferable. These can be used alone or in combination of two or more.

The graft ratio of the transparent ABS resin is preferably 10 to 100%, more preferably 15 to 90%, and particularly preferably 20 to 70%. If the graft ratio is less than 10%, the resulting transparent thermoplastic resin molded product may have poor appearance and reduced impact strength. On the other hand, if it exceeds 100%, the moldability may deteriorate. There is.
Here, the graft ratio (%) is a value determined by the following formula, where x is the weight of the rubber component in 1 g of the rubber-reinforced polymer and y is the weight of methyl ethyl ketone insoluble matter. Graft rate (%) = [(y−x) / x] × 100

  In addition, the intrinsic viscosity [η] (measured in methyl ethyl ketone at 30 ° C.) of the methyl ethyl ketone soluble component which is a matrix component of the transparent ABS resin is preferably 0.1 to 1.0 dl / g, more preferably 0.2 to 0.9 dl / g, particularly preferably 0.3 to 0.7 dl / g. When the intrinsic viscosity [η] is within the above range, a transparent thermoplastic resin molded article excellent in impact resistance and molding processability (fluidity) can be obtained. The graft ratio (%) and intrinsic viscosity [η] can be easily controlled by changing the type and amount of the polymerization initiator, chain transfer agent, emulsifier, solvent, etc., and the polymerization time and polymerization temperature. Can do.

  Further, the difference between the refractive index of the rubbery polymer (rubber component) of the transparent ABS resin and the refractive index of the matrix resin is preferably 0.05 or less, more preferably 0.02 or less, and particularly preferably 0.01 or less. It is. When the difference in refractive index is within the above range, a transparent thermoplastic resin molded article having good transparency can be obtained.

The transparent thermoplastic resin preferably contains an acrylic resin.
This acrylic resin can be obtained by polymerizing a (meth) acrylic acid ester compound alone or copolymerizing with a copolymerizable vinyl monomer. Specifically, acrylic resins include methyl methacrylate homopolymer, methyl methacrylate and methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. And alkyl (meth) acrylic acid esters such as 2-ethylhexyl (meth) acrylate, or copolymers with aromatic vinyl monomers such as styrene, α-methylstyrene and vinyltoluene.
The weight average molecular weight of the acrylic resin is preferably 50,000 to 400,000 as measured by GPC method using tetrahydrofuran as a solvent. When the weight average molecular weight is within the above range, the molding processability is excellent, and the resulting transparent thermoplastic resin molded article is excellent in impact resistance and toughness.
The acrylic resin may be used by mixing two or more acrylic resins having different weight average molecular weights as long as the weight average molecular weight as a whole falls within the above range.

The transparent thermoplastic resin preferably contains a polycarbonate resin.
The polycarbonate resin is not particularly limited as long as it has a carbonate bond in the main chain, and an aromatic polycarbonate can be used, and an aliphatic polycarbonate can also be used. Moreover, these can also be used in combination.
In the present invention, an aromatic polycarbonate is preferable from the viewpoint of impact resistance, heat resistance, and the like. The polycarbonate resin may have a terminal modified with an R—CO— group or an R′—O—CO— group (R and R ′ each represents an organic group). Polycarbonate resins can be used alone or in combination of two or more.

The viscosity average molecular weight of the polycarbonate resin is preferably 12,000 to 40,000 when converted from the solution viscosity measured at a temperature of 20 ° C. using methylene chloride as a solvent. When this viscosity average molecular weight is in the above range, the molding processability is excellent, and the resulting molded article is excellent in impact resistance, toughness and chemical resistance.
The polycarbonate resin may be used by mixing two or more polycarbonate resins having different viscosity average molecular weights as long as the overall viscosity average molecular weight falls within the above range.

Moreover, in the said 3rd invention, the said transparent thermoplastic resin composition is a particulate form, The number average particle diameter is 300-3000 micrometers .
Thereby , the transparent thermoplastic resin composition can be smoothly filled in the cavity of the rubber mold.

The particulate transparent thermoplastic resin composition preferably has a bulk density of 0.4 g / cm ³ or more. In this case, when the particulate transparent thermoplastic resin composition is heated by the electromagnetic wave including the wavelength region of 0.78 to 2 μm, the temperature rise rate of the transparent thermoplastic resin composition is too high. And it can prevent that malfunctions, such as a burning, arise in this transparent thermoplastic resin composition.
The bulk density can be determined by a method based on JIS K7365. The particulate transparent thermoplastic resin composition can have a substantially uniform particle size, or can be a mixture of a plurality of types of particles having different average particle sizes or particle size distributions.

Moreover, it is preferable to use the thing close | similar to a spherical form as a particulate transparent thermoplastic resin composition in order to enlarge bulk density.
As the particulate transparent thermoplastic resin composition, it is possible to use a thermoplastic resin pellet produced by freeze-grinding. According to freeze pulverization, particulate transparent thermoplastic resin compositions having various particle sizes can be produced. Moreover, as a particulate transparent thermoplastic resin composition, what was produced by what is called an underwater cut system which attached the die | dye of a narrow diameter to the front-end | tip of an extruder can also be used.
According to this extruded water cut method, particles of about 1 mm (particulate transparent thermoplastic resin composition) can be produced easily and inexpensively.

In the third and fourth inventions, after performing the heating step and before performing the cooling step, 0.1 to 5 MPa of a molten transparent thermoplastic resin is placed in the space left in the cavity. it is preferable to perform the filling step of filling an injection pressure (claim 6).
In this case, after the heating step, the space left in the cavity due to the melting of the transparent thermoplastic resin composition is filled with a molten thermoplastic resin as a filling step. At this time, the part where the transparent thermoplastic resin composition was present in the cavity of the rubber mold before the heating step, the part located in the lower side in the vertical direction in the cavity of the rubber mold, or the surface of the cavity of the rubber mold Is filled with a transparent thermoplastic resin obtained by melting the transparent thermoplastic resin composition, and the filling amount of the molten transparent thermoplastic resin to be newly filled can be reduced.

Thereby, it is possible to fill the entire cavity with the transparent thermoplastic resin without increasing the filling pressure so much that the deformation and opening of the rubber mold can be effectively suppressed. Therefore, resin leakage from the split surface (parting surface) in the rubber mold can be prevented, and when a transparent thermoplastic resin molded product is obtained by the cooling process, the appearance, shape and surface of this transparent thermoplastic resin molded product are obtained. The quality such as accuracy and the mechanical strength can be effectively improved.
In order to fill the rubber mold cavity almost uniformly with the transparent thermoplastic resin, it is preferable that the injection pressure is 0.1 MPa or more to prevent deformation of the rubber mold and resin leakage from the rubber mold cavity. In order to prevent this, the injection pressure is preferably 5 MPa or less.
Moreover, the transparent thermoplastic resin in the said transparent thermoplastic resin composition and the said transparent thermoplastic resin of a molten state can be made into the same composition.

In the fourth aspect of the invention, in the arranging step, the small transparent thermoplastic resin particles are previously placed in the inner wall surface of the rubber mold cavity in the opened state or in the rubber mold cavity in the closed state. It is preferable that the large transparent thermoplastic resin particles are placed in the closed cavity of the rubber mold after being placed in ( 3 ).

  In this case, in the arranging step, after the small transparent thermoplastic resin particles are attached to the inner wall surface of the cavity, the large transparent thermoplastic resin particles are passed through the inside of the small transparent thermoplastic resin particles in the cavity. Can do. Therefore, the filling of the transparent thermoplastic resin particles into the cavity can be performed more smoothly. Thereby, a transparent thermoplastic resin molded product excellent in quality such as appearance, shape, surface accuracy, and mechanical strength can be obtained.

Further, the small thermoplastic resin particles can be easily adhered to the inner wall surface of the cavity by being sprinkled (sprinkled) on the surface of the open rubber mold cavity.
The large transparent thermoplastic resin particles and the small transparent thermoplastic resin particles can have the same composition. Moreover, the composition of the said transparent thermoplastic resin of a molten state can be made the same with the transparent thermoplastic resin in a large transparent thermoplastic resin particle and a small transparent thermoplastic resin particle.

The large transparent thermoplastic resin particles preferably have a bulk density of 0.4 g / cm ³ or more.
In the arrangement step, the cavity can be filled in the state where the transparent thermoplastic resin composition is heated and melted.

Further, at least one of the timing from the previous said placement step before the heating step, it is preferable to perform vacuum step of the space left in the cavity or the cavity in a vacuum state (claim 7).
In this case, by performing a vacuum process, it is possible to more easily fill the melted transparent thermoplastic resin particles into the cavity, and to produce a transparent thermoplastic resin molded article excellent in appearance without bubbles. Can be easily obtained.
In addition, a vacuum process can be performed at the timing of at least any one before an arrangement | positioning process, before and after an arrangement | positioning process, a particle | grain heating process, before and after a particle | grain heating process, the said filling process, or a filling process.
Further, the vacuum state does not mean only an absolute vacuum state but also a reduced pressure state with respect to an atmospheric pressure state.

Examples of the transparent thermoplastic resin composition of the present invention, a transparent thermoplastic resin molded article using the same, and a method for producing the same will be described below with reference to the drawings.
The transparent thermoplastic resin composition 6A of this example is filled in the cavity 22 of the rubber mold 2 made of a rubber material, and heated and melted by irradiating the rubber mold 2 with an electromagnetic wave including a wavelength region of 0.78 to 2 μm. It is for making it happen. The transparent thermoplastic resin composition 6A has an infrared absorber of 0.0005 to 0 with respect to 100 parts by mass of the transparent thermoplastic resin so that the haze value when the transparent thermoplastic resin molded product 60 is 20% or less. .1 part by mass is contained.

Hereinafter, the transparent thermoplastic resin composition 6A of this example, the transparent thermoplastic resin molded product 60 using the same, and the manufacturing method thereof will be described in detail with reference to FIGS.
The transparent thermoplastic resin used in this example is an ABS resin which is a rubber-reinforced styrene resin having amorphous properties.
The rubber mold 2 of this example is made of a transparent or translucent silicone rubber. In this rubber mold 2, a master model (handmade product etc.) of a transparent thermoplastic resin molded product 60 to be molded is placed in a liquid silicone rubber, the silicone rubber is cured, and the cured silicone rubber is cut open. It can be produced by taking out the master model from this silicone rubber. In addition, when the silicone rubber is cut open, when the split mold parts 21 are combined, the alignment of the split mold parts 21 can be made accurate by forming the split surfaces 20 having various corrugated shapes. .

  Further, as shown in FIG. 1, the rubber mold 2 of this example is formed by forming one dividing surface 20 and combining two dividing mold parts 21. On the other hand, when the shape of the transparent thermoplastic resin molded product 60 to be molded is complicated, the rubber mold 2 can be formed by combining three or more divided mold portions 21. At the time of molding, the plurality of divided mold parts 21 are held in a combined state by means for preventing mold opening.

  In the method for producing the transparent thermoplastic resin molded product 60 of this example, after the particulate transparent thermoplastic resin composition 6A is disposed in the cavity 22 of the rubber mold 2, the molding apparatus 1 is used to form the cavity of the rubber mold 2. The transparent thermoplastic resin 6 is injection molded to 22. As shown in FIGS. 1 to 3, the molding apparatus 1 includes the following pressure vessel 3, vacuum pump 31, injection cylinder 52, injection cylinder 53, electromagnetic wave generation means 4, and filter 43.

The transparent thermoplastic resin composition 6A of this example is in the form of particles, contains 0.1 to 20% by mass of small transparent thermoplastic resin particles 62 having a particle diameter of 1 to 100 μm, and the balance is the small transparent thermoplastic resin. The large transparent thermoplastic resin particles 61 are larger than the resin particles 62. The particle size of the large transparent thermoplastic resin particles 61 in this example is greater than 100 μm and not greater than 3000 μm.
The large transparent thermoplastic resin particles 61 and the small transparent thermoplastic resin particles 62 contain 0.0005 to 0.1 parts by mass of an infrared absorber with respect to 100 parts by mass of the thermoplastic resin 61. Become.

  The pressure vessel 3 is configured to accommodate the rubber mold 2, and is configured to form a vacuum state by a vacuum pump 31 connected to the pressure vessel 3. The injection cylinder 52 is configured to inject the large transparent thermoplastic resin particles 61 in the transparent thermoplastic resin composition 6 </ b> A into the cavity 22 through the injection portion 23 formed in the rubber mold 2. The injection cylinder 53 is configured to inject the molten transparent thermoplastic resin 6B into the cavity 22 through the injection portion 23 formed in the rubber mold 2 at a predetermined pressure. In this example, the pressure of the molten transparent thermoplastic resin 6B injected from the injection cylinder 53 into the rubber mold 2 is 0.1 to 5 MPa.

The electromagnetic wave generating means 4 includes an electromagnetic wave (light) generating source 41 and a reflector (reflecting plate) 42 for guiding the electromagnetic wave generated by the generating source 41 in the direction of the rubber mold 2. As the electromagnetic wave generating means 4 of this example, a near infrared halogen heater having a light intensity peak in the vicinity of about 1.2 μm in the near infrared region is used. This near infrared halogen heater is configured to emit an electromagnetic wave including a wavelength region of 0.78 to 4 μm. The filter 43 of this example is quartz glass that reduces the amount of transmission of electromagnetic waves having a wavelength exceeding 2 μm.
2 and 3, an electromagnetic wave emitted from the electromagnetic wave generating means 4 is indicated by an arrow X.

  In addition, the absorbance to electromagnetic waves (light) including a wavelength region of 0.78 to 2 μm (a measure indicating the absorption intensity with respect to light of a specific wavelength) is the rubber rubber of the ABS resin used as the transparent thermoplastic resin 6. It is larger than the silicone rubber used as the mold 2. The absorbance can be measured using, for example, Shimadzu UV3100.

  FIG. 4 shows the light transmittance of each silicone rubber, with wavelength (nm) on the horizontal axis and light transmittance (%) on the vertical axis for transparent silicone rubber and translucent silicone rubber. It is a graph. In the figure, it can be seen that each silicone rubber transmits light having a wavelength between 200 and 2200 (nm). For this reason, when the surface of the rubber mold 2 made of silicone rubber is irradiated with near-infrared rays (light having a wavelength range of 0.78 to 2 μm) that is in this wavelength region, most of the near-infrared rays are transmitted through the rubber mold 2 The transparent thermoplastic resin composition 6A can be absorbed. Then, it can be seen that the transparent thermoplastic resin composition 6A can be selectively heated as compared with the rubber mold 2.

  FIG. 5 shows the wavelength on the horizontal axis for a thermoplastic resin not containing an infrared absorber (shown by a broken line) and a thermoplastic resin composition (shown by a solid line) in which an infrared absorber is contained in a thermoplastic resin. It is a graph which shows the difference in the light absorption rate, taking (nm) and taking the light absorption rate (%) on the vertical axis. In the same figure, in comparison with a thermoplastic resin not containing an infrared absorber, a thermoplastic resin composition containing an infrared absorber in a thermoplastic resin has a near infrared ray containing a wavelength region of 0.78 to 2 μm. It can be seen that the absorption rate can be increased. In addition, the thermoplastic resin which does not contain an infrared absorber shows the result of the comparative product 1 in the confirmation test mentioned later, and the thermoplastic resin composition which made the thermoplastic resin contain the infrared absorber is the invention in the confirmation test mentioned later. The result of product 2 is shown.

Next, the order of manufacturing the transparent thermoplastic resin molded product 60 using the molding apparatus 1 will be described in detail.
In the manufacturing method of the transparent thermoplastic resin molded product 60 of this example, the transparent thermoplastic resin composition 6A and the molten thermoplastic resin composition 6A are melted when the transparent thermoplastic resin 6 is molded by filling the rubber mold 2 with the transparent thermoplastic resin 6. The transparent thermoplastic resin 6B in a state is used. In this example, an ABS resin having the same composition is used for the transparent thermoplastic resin and the molten thermoplastic resin 6B in the transparent thermoplastic resin composition 6A. The large transparent thermoplastic resin particles 61 and the small transparent thermoplastic resin particles 62 used as the thermoplastic resin composition 6A are blended with an infrared absorber at the same blending ratio.

In forming the transparent thermoplastic resin molded product 60, first, as shown in FIG. 1, the particle diameter is 1 on the inner wall surface 221 of the cavity 22 in the split mold portion 21 of the rubber mold 2 in the open state as shown in FIG. A small transparent thermoplastic resin particle 62 having a size of ˜100 μm is sprinkled and arranged.
Subsequently, the injection cylinder 52 is set in the injection part 23 of the rubber mold 2 in a closed state, and large transparent thermoplastic resin particles 61 having a particle diameter of more than 100 μm and not more than 3000 μm are placed in the cavity 22 of the rubber mold 2. throw into. At this time, the content ratio of the transparent thermoplastic resin particles 61 and 62 in the transparent thermoplastic resin composition 6A put into the cavity 22 is 80-99.9% by mass of the large transparent thermoplastic resin particles 61, and the small transparent The thermoplastic resin particles 62 should be 0.1 to 20% by mass. Then, almost the entire cavity 22 is filled with the transparent thermoplastic resin composition 6A.

  When the small transparent thermoplastic resin particles 62 are sprinkled on the inner wall surface 221 of the cavity 22, most of the small transparent thermoplastic resin particles 62 adhere to the inner wall surface 221 of the cavity 22. Here, the rubber mold 2 of this example is made of silicone rubber, and the small transparent thermoplastic resin particles 62 have a particle diameter of 1 to 100 μm, so that they are formed on the inner wall surface 221 of the cavity 22 made of silicone rubber. It can be attached effectively.

  When the large transparent thermoplastic resin particles 61 are put into the closed cavity 22 of the rubber mold 2, the small transparent thermoplastic resin particles 62 are attached to the inner wall surface 221 of the cavity 22. Thereby, the large transparent thermoplastic resin particles 61 can pass (drop) inside the small transparent thermoplastic resin particles 62 in the cavity 22. Therefore, the filling of the thermoplastic resin particles 61 and 62 into the cavity 22 can be performed smoothly. In addition, the small transparent thermoplastic resin particles 62 and the large transparent thermoplastic resin particles 61 can be filled by adding vibration or airflow, in addition to filling by the dead weight.

Next, as shown in FIG. 2, as a vacuum process, the vacuum pump 31 evacuates the pressure vessel 3 to make the space 220 left in the cavity 22 of the rubber mold 2 into a vacuum state.
Next, as shown in the figure, as a heating process, the electromagnetic wave including the wavelength region of 0.78 to 4 μm emitted from the electromagnetic wave generating means 4 is transmitted through the filter 43, and the transmitted electromagnetic wave after being transmitted through the filter 43 is The transparent thermoplastic resin composition 6A in the cavity 22 is irradiated through the rubber mold 2. At this time, the transparent thermoplastic resin composition 6A can be selectively heated compared to the rubber mold 2 due to the difference in physical properties between the rubber material constituting the rubber mold 2 and the transparent thermoplastic resin composition 6A ( The heating amount of the transparent thermoplastic resin composition 6A can be increased). Thereby, the temperature rise of the rubber mold 2 can be suppressed and the transparent thermoplastic resin composition 6A can be melted.

In addition, since the large transparent thermoplastic resin particles 61 are mixed with an infrared absorber, the electromagnetic wave can be effectively absorbed even when a transparent thermoplastic resin is used as the thermoplastic resin. The plastic resin composition 6A can be rapidly heated and melted.
In the cavity 22, a space 220 for newly filling the thermoplastic resin 6 is formed by melting the transparent thermoplastic resin composition 6 </ b> A.

  In addition, the state of the cavity 22 after performing the said heating process will be in various states depending on the molding conditions. For example, when the fluidity of the thermoplastic resin 6 is poor, it is difficult for the molten thermoplastic resin 6 to sink down below the cavity 22, and a foaming state is formed in which a large number of bubbles are formed near the center of the cavity 22. it is conceivable that. In addition, when the fluidity of the thermoplastic resin 6 is good, it is considered that the molten thermoplastic resin 6 is in a state of sinking below the cavity 22. Further, as in this example, when the vacuum process is performed, the rubber mold 2 is deformed, the gap (space 220) in the cavity 22 is crushed, and the thermoplastic resin 6 is present on the inner wall surface 221 of the cavity 22. I think that.

  Next, as shown in FIG. 3, as a filling step, the injection cylinder 53 is set in the injection portion 23 of the rubber mold 2, and the molten thermoplastic resin 6 </ b> B is placed in the space 220 left in the cavity 22 in an amount of 0.1 to 5 MPa. Fill with the injection pressure of. Further, in the filling step of this example, irradiation of the transmitted electromagnetic wave to the thermoplastic resin 6 through the rubber mold 2 is continued, and the thermoplastic resin 6 in the cavity 22 is heated.

When the thermoplastic resin 6B in the molten state is filled, a thermoplastic resin in which the transparent thermoplastic resin composition 6A is melted is disposed on a portion located on the inner wall surface 221 (rubber surface) of the cavity 22 of the rubber mold 2. 6 is filled, and the filling amount of the molten thermoplastic resin 6B to be newly filled can be reduced.
Thereby, the thermoplastic resin 6 can be filled in the entire cavity 22 without increasing the filling pressure (injection pressure) so much that the deformation and opening of the rubber mold 2 can be effectively suppressed. Therefore, resin leakage from the split surface (parting surface) 20 in the rubber mold 2 can be prevented, and when the transparent thermoplastic resin molded product 60 is obtained through the cooling process, the transparent thermoplastic resin molded product 60 is obtained. It is possible to effectively improve the quality, such as appearance, shape, surface accuracy, and mechanical strength.
Moreover, the thermoplastic resin of the same composition is used for the transparent thermoplastic resin and the molten thermoplastic resin 6B in the transparent thermoplastic resin composition 6A (large transparent thermoplastic resin 61 and small transparent thermoplastic resin 62). Therefore, it is possible to prevent the boundary surface of the resin from being formed in the transparent thermoplastic resin molded product 60 after molding.

Therefore, according to the resin molding method of this example, the transparent thermoplastic resin molded product 60 having a haze value of 20% or less representing the transparency of the resin is rapidly molded by electromagnetic wave irradiation molding by blending the infrared absorber. be able to. In addition, the rubber mold 2 as a mold can be easily manufactured, and the transparent thermoplastic resin molded product 60 having various shapes can be molded at low cost.
Further, when the thermoplastic resin 6 is molded using the rubber mold 2, the quality, mechanical strength, and the like of the transparent thermoplastic resin molded product 60 such as appearance, shape, and surface accuracy can be effectively improved. In addition, the effect of this example can be particularly prominent when the transparent thermoplastic resin molded product 60 to be molded has a large or thin shape, or when the viscosity of the thermoplastic resin 6 used for molding is high. it can.

(Simulation of effect by using large and small transparent thermoplastic resin particles 61 and 62)
6 and 7 show an enlarged view of the state in which the transparent thermoplastic resin particles 61 and 62 are filled in the cavity 22 of the rubber mold 2. FIG. 6 shows a case where the large transparent thermoplastic resin particles 61 and the small transparent thermoplastic resin particles 62 are filled in the cavity 22, and FIG. 7 shows only the large transparent thermoplastic resin particles 61 in the cavity 22. The case of filling is shown.
As shown in FIG. 7, when trying to fill only the large transparent thermoplastic resin particles 61 into the cavity 22, the large transparent thermoplastic resin particles 61 adhere to the inner wall surface 221 of the cavity 22, and the large transparent thermoplastic resin. It is considered that it is difficult for another large transparent thermoplastic resin particle 61 to pass (drop) (indicated by arrow T) inside the particle 61.

  On the other hand, as shown in FIG. 6, when the large transparent thermoplastic resin particles 61 are filled after the small transparent thermoplastic resin particles 62 are filled in the cavity 22, the small transparent thermoplastic resin particles 62 are effective. The large transparent thermoplastic resin particles 61 adhere to the inner wall surface 221 of the cavity 22 and pass (drop) inside the small transparent thermoplastic resin particles 62 with almost no adhesion to the inner wall surface 221 of the cavity 22 ( (Indicated by an arrow T.) Thereby, according to the said transparent thermoplastic resin particle composition 6A, it thinks that the substantially whole cavity 22 can be filled effectively.

(Confirmation test)
In this confirmation test, it was confirmed whether the time required for the transparent thermoplastic resin composition 6A to melt can be shortened by blending the infrared absorber.
Specifically, the transparent thermoplastic resin formed by blending resins 1 to 3 as transparent thermoplastic resins not blended with an infrared absorber as comparative products 1 to 3, and blending an infrared absorber with the resins 1 to 3 Composition 6A as invention products 1-8, time required for melting invention products 1-8 and comparison products 1-3 (time to reach 260 ° C. in this confirmation test) (minutes), The haze value (%) was measured. Moreover, the temperature and time for obtaining a molded article were adjusted as appropriate.

The transparent thermoplastic resins subjected to the above measurement in this confirmation test were the following resins 1 to 3.
(Resin 1) Transparent ABS resin (“Techno ABS830” manufactured by Technopolymer Co., Ltd., MFR 30 g / 10 min (220 ° C., 98 N)) has a haze value of 4% with a test piece having a thickness of 2.5 mm.
(Resin 2) An acrylic resin (“ACRYPET VH001” manufactured by Mitsubishi Rayon Co., Ltd., MFR 2 g / 10 min (230 ° C., 37.3 N)) has a haze of 0.2% with a test piece having a thickness of 2.5 mm.
(Resin 3) Polycarbonate resin (“NOVALEX 7020A” manufactured by Mitsubishi Engineering Plastics, MFR 30 g / 10 min (300 ° C., 11.8 N)), and the haze value by a test piece having a thickness of 2.5 mm is 0.4%. .
As the infrared absorber, “Lumogen IR1050” manufactured by BASF was used.
Table 1 shows the compositions of Invention products 1 to 8 and Comparative products 1 to 3, and the results of measuring the melting time (min) and haze value (%) for these.

Inventive products 1 to 8 are blended with infrared absorbers at the blending ratios shown in Table 1 with respect to resins 1 to 3, and extruded with a single screw type extruder (40 mmφ, cylinder temperature 220 to 260 ° C.). The thermoplastic resin particles were produced as transparent thermoplastic resin particles having a number average particle diameter of 700 μm using the transparent thermoplastic resin particles as a raw material and an extruder with a strand cutting equipment (for micropellets) manufactured by GALA. . The transparent thermoplastic resin particles had a bulk density of 0.63 g / cm ³ measured according to JIS K7365.
Comparative products 1 to 3 were produced as transparent thermoplastic resin particles having a number average particle diameter of 700 μm in the same manner as described above with respect to resins 1 to 3 not containing an infrared absorbent.

Further, the cavity 22 of the rubber mold 2 made of silicone rubber is formed into a rectangular shape having a length of 80 mm × width of 55 cm × thickness of 2.5 mm and heated by a halogen heater until the temperature reaches 260 ° C. from normal temperature. The time required for (melting time) was measured.
The haze value in this confirmation test is obtained by using a test piece (molded product) molded into a size of length 80 mm × width 55 cm × thickness 2.5 mm and a measuring instrument (haze guard plus manufactured by Gardner). , Measured according to JIS K7136. The haze value is closer to transparency as the value is smaller.

From Table 1, it can be seen that the transparent thermoplastic resin composition 6A containing an infrared absorber has a higher haze value than a transparent thermoplastic resin not containing an infrared absorber. On the other hand, when the infrared absorber is blended (invention products 1 to 8), the melting time is greatly shortened compared to the case where the infrared absorber is not blended (comparative products 1 to 3). I understand. It can also be seen that the melting time is further shortened by increasing the blending ratio of the infrared absorber. However, it can be seen that as the blending ratio of the infrared absorber increases, the haze value increases and the transparency decreases.
From the above results, it is possible to reduce the time required for the thermoplastic resin to melt by including the infrared absorbent in the transparent thermoplastic resin, and a transparent thermoplastic resin molded article having a haze value of 20% or less. It can be seen that 60 can be formed in a short time.

DESCRIPTION OF SYMBOLS 1 Molding apparatus 2 Rubber mold 22 Cavity 4 Electromagnetic wave generating means 6A Transparent thermoplastic resin composition 6B Transparent thermoplastic resin in a molten state 60 Transparent thermoplastic resin molded product 61 Large transparent thermoplastic resin particles 62 Small transparent thermoplastic resin particles

Claims (7)

In addition to having an infrared absorber of 0.0005 to 0.1 parts by mass with respect to 100 parts by mass of the transparent thermoplastic resin and having a transparent thermoplastic resin molded product, the haze value is 20% or less and several A method for producing a transparent thermoplastic resin molded article using a particulate transparent thermoplastic resin composition having an average particle diameter of 300 to 3000 μm,
An arrangement step of arranging the transparent thermoplastic resin composition in a cavity of a rubber mold made of a rubber material;
A heating step of irradiating the transparent thermoplastic resin composition in the cavity through the rubber mold with an electromagnetic wave containing a wavelength region of 0.78 to 2 μm to heat and melt the transparent thermoplastic resin composition; ,
A cooling step of cooling the molten transparent thermoplastic resin composition to obtain a transparent thermoplastic resin molded product, and a method for producing a transparent thermoplastic resin molded product. With respect to 100 parts by mass of the transparent thermoplastic resin, the infrared value of 0.0005 to 0.1 part by mass, and when the transparent thermoplastic resin molded product has a haze value of 20% or less, From large transparent thermoplastic resin particles that are in the form of particles and contain 0.1 to 20% by mass of small transparent thermoplastic resin particles having a particle diameter of 1 to 100 μm, with the remainder being larger than the small transparent thermoplastic resin particles A method for producing a transparent thermoplastic resin molded article using a transparent thermoplastic resin composition comprising:
An arrangement step of arranging the transparent thermoplastic resin composition in a cavity of a rubber mold made of a rubber material;
A heating step of irradiating the transparent thermoplastic resin composition in the cavity through the rubber mold with an electromagnetic wave containing a wavelength region of 0.78 to 2 μm to heat and melt the transparent thermoplastic resin composition; ,
A cooling step of cooling the molten transparent thermoplastic resin composition to obtain a transparent thermoplastic resin molded product, and a method for producing a transparent thermoplastic resin molded product.   In claim 2, in the arrangement step, after the small transparent thermoplastic resin particles are first arranged in the inner wall surface of the rubber mold cavity in the open state or in the rubber mold cavity in the closed state, A method for producing a transparent thermoplastic resin molded article, wherein the large transparent thermoplastic resin particles are put into a closed cavity of the rubber mold.   The method for producing a transparent thermoplastic resin molded article according to any one of claims 1 to 3, wherein the transparent thermoplastic resin is amorphous.   5. The transparent thermoplastic resin according to claim 1, wherein the transparent thermoplastic resin is obtained by polymerizing a monomer component containing 50% by mass or more of a (meth) acrylic acid ester compound in the presence of a rubbery polymer. A transparent heat characterized in that it is a mixture obtained by mixing the rubber-reinforced vinyl resin obtained or the rubber-reinforced vinyl resin and a (co) polymer containing a structural unit derived from a vinyl monomer. A method for producing a plastic resin molded article.   In any one of Claims 1-5, after performing the said heating process, before performing the said cooling process, in the space left in the said cavity, 0.1-0.1% of molten thermoplastic resin is made into a molten state. A method for producing a transparent thermoplastic resin molded article, comprising performing a filling step of filling with an injection pressure of 5 MPa.   The vacuum process for making the cavity or the space left in the cavity a vacuum state is performed at least at any timing from the arrangement process to the heating process. A method for producing a transparent thermoplastic resin molded product.

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