JP2023043837A - Method for manufacturing molded article made of crystalline resin composition - Google Patents

Abstract

To provide a method for manufacturing a molded article made of a crystalline resin composition that suppresses residual strain, greatly improves toughness, and has an excellent weld property.SOLUTION: There is provided a method for manufacturing a molded article, in which a heat and cool molding is performed that is configured to perform an injection process in a state in which a crystalline resin composition containing at least one kind of crystalline resin is heated in a range where a mold cavity surface temperature is higher than a cooling crystallization temperature of the crystalline resin composition and is lower than a melting point and, after injection process, cool the mold cavity surface temperature to the cooling crystallization temperature or lower of the crystalline resin composition.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a method for producing a molded article made of a crystalline resin composition. More particularly, the present invention relates to a method for producing a molded article made of a crystalline resin composition that has greatly improved toughness by suppressing residual strain by heat-and-cool molding under specific conditions.

Crystalline resins such as polyamide resins, polyester resins, and polyphenylene sulfide resins have excellent mechanical properties, chemical resistance, fluidity, and heat resistance. Widely used for parts. In general, crystalline resins with a small molecular weight have high fluidity and rigidity, but low toughness. On the other hand, crystalline resins with large molecular weights require high injection pressure in conventional molding methods, and such molding methods have the problem of leaving a large amount of residual strain in the molded product and reducing toughness.

Gas-assisted molding, for example, has been studied as a method of molding resin at low pressure (see, for example, Patent Document 1).

Japanese Unexamined Patent Application Publication No. 2001-191368

However, in the gas-assisted molding described in Patent Document 1, although the injection pressure can be lowered and the residual strain of the molded product can be reduced, gas remains in the molded product, resulting in a decrease in toughness and brittleness. rice field.

SUMMARY OF THE INVENTION In view of the above problems of the prior art, an object of the present invention is to provide a molded article made of a crystalline resin composition that suppresses residual strain and has excellent toughness.

In order to achieve the above objects, the present invention has the following configurations.

A crystalline resin composition containing at least one kind of crystalline resin is heated to a mold cavity surface temperature higher than the cooling crystallization temperature and lower than the melting point of the crystalline resin composition. A method for producing a molded product, characterized by performing heat and cool molding, in which an injection step is performed, and after the injection step, the surface temperature of the mold cavity is cooled to a temperature-lowering crystallization temperature or less of the crystalline resin composition.

According to the method for producing a molded article made of a crystalline resin of the present invention, it is possible to provide a molded article made of a crystalline resin composition that suppresses residual strain and has excellent toughness. In addition, the molded article is excellent in tensile properties (weld properties) of the weld portion.

The present invention will now be described in more detail.

The present invention provides a crystalline resin composition containing at least one kind of crystalline resin, wherein the cavity surface temperature of the mold is higher than the temperature-lowering crystallization temperature and lower than the melting point of the crystalline resin composition. A molded product characterized by performing heat and cool molding, in which the injection step is performed in a state where the resin composition is heated to a temperature of 100°C, and after the injection step, the cavity surface temperature of the mold is cooled to the cooling crystallization temperature or less of the crystalline resin composition. manufacturing method.

The heat and cool molding of the present invention will be explained. The heat and cool molding of the present invention is a type of injection molding, in which the cavity surface temperature of the mold is heated to a range higher than the cooling crystallization temperature of the crystalline resin composition and lower than the melting point in the molding process. is a molding method in which an injection step is performed at , and after the injection step, the cavity surface temperature of the mold is cooled to below the cooling crystallization temperature of the crystalline resin composition. Specifically, the injection step is performed in a state in which the surface temperature of the mold cavity is higher than the crystallization temperature of the crystalline resin composition and lower than the melting point, and the surface of the mold cavity is immediately after the injection step. This is a molding method in which the temperature is cooled to a temperature lower than the crystallization temperature of the crystalline resin composition. Methods for raising the cavity surface temperature of the mold include, for example, a method of raising the temperature with pressurized steam or pressurized hot water, a method of raising the temperature with heating oil, a method of raising the temperature with heater heating, and an electromagnetic induction heating method. A method of raising the temperature can be mentioned. Although the heating rate of the mold changes depending on the heating method, any of the above-described methods capable of raising the mold temperature are preferable. Examples of the method for cooling the cavity surface temperature of the mold include a method of cooling with cooling water or cooling oil, and a method of cooling by slow cooling, but the cooling method with cooling water is preferable from the viewpoint of the cooling rate.

In the molding process of the present invention, when the injection step is performed while the cavity surface temperature of the mold is heated to the cooling crystallization temperature or lower of the crystalline resin composition, the resulting molded article has a progressed orientation of the resin. Since the residual strain increases, the toughness tends to decrease. Also, the orientation progresses, so the weld characteristics are inferior. On the other hand, when the injection process is performed while the cavity surface temperature of the mold is heated to the melting point or higher of the crystalline resin composition, the resin tends to flow, the molded product tends to have burrs, and the molded product cannot be obtained. In addition, if the molded article is taken out in a state where the cavity surface temperature of the mold after the injection step is higher than the cooling crystallization temperature of the crystalline resin composition, the molded article is likely to be deformed.

By performing the heat and cool molding of the present invention, the orientation in the molded article made of the crystalline resin composition containing at least one kind of crystalline resin is suppressed, and the residual strain is reduced. A molded article having excellent weld properties can be obtained.

For example, by performing the heat and cool molding of the present invention, a molded article made of a crystalline resin composition containing a polyamide resin, which is a type of crystalline resin, is formed at equal intervals in the thickness direction from the surface of the molded article. The average value of the orientation parameters measured at locations is in the range of 0.9 to 1.1, the standard deviation of the orientation parameters is controlled to 0.15 or less, the residual strain is small, the toughness is excellent, and the weld characteristics are excellent. . The orientation parameter is an index representing the orientation of the crystalline resin in the molded product. When it exceeds, it indicates that the orientation progresses in the direction perpendicular to the resin flow direction during molding.

The average value of the orientation parameters measured at 12 points in the thickness direction from the surface of the molded article is in the range of 0.9 to 1.1, and the standard deviation of the orientation parameters is controlled to 0.15 or less. , the orientation is small and the residual strain is small, so the toughness is improved. Furthermore, the weld property is excellent, and the dimensional stability is excellent because the variation in orientation is reduced.

In addition, since the toughness and weld characteristics of the molded product can be further improved, the average value of the orientation parameters measured at 12 points at equal intervals in the thickness direction from the surface of the molded product should be in the range of 0.92 to 1.08. It is preferably in the range of 0.94 to 1.06.

In addition, the standard deviation of the orientation parameter measured at 12 points at equal intervals in the thickness direction from the surface of the molded product is preferably 0.12 or less, more preferably 0.10, because the molded product has more excellent dimensional stability. The following are preferable. The standard deviation has a minimum value of 0, and a smaller standard deviation means a smaller local orientation, and the smaller the standard deviation, the better.

Here, the orientation parameters measured at 12 points at equal intervals in the thickness direction from the surface of the molded article are measured using laser Raman spectroscopy. Measurement examples are given below. For example, a sample is cut out from a molded article made of a crystalline resin composition containing a polyamide resin. A microtome is used to expose the cross section of the cut sample so that a surface parallel to the resin flow direction appears. Using the surface-exposed sample, polarized Raman spectra are obtained at 12 points at equal intervals in the thickness direction from the surface of the molded article using "in Via" manufactured by RENISHAW. Specifically, a laser beam of 785 mm is oscillated from a semiconductor laser and focused on a sample using a 20-fold objective lens (NA=0.4). The laser intensity at the sample position is 200 mW. Photons scattered on the sample surface are spectroscopically separated using a diffraction grating of 1200 lines/mm. The slit width in front of the spectroscope is 65 mm. Spectroscopic photons are detected by a CCD (Peltier cooling, number of channels). The resin flow direction of the sample is defined as 0 degrees, and polarized Raman spectra are acquired in the 0-degree direction and the 90-degree direction. In the 0-degree direction, polarized light parallel to the 0-degree direction is incident, and only the component parallel to the 0-degree direction is detected out of the obtained scattered light. In the 90-degree direction, polarized light parallel to the 90-degree direction is incident, and only the component parallel to the 90-degree direction is detected out of the obtained scattered light. For the obtained polarized Raman spectrum, the analysis software WiRE is used to calculate the peak intensities of the Raman bands near 1440 cm ⁻¹ and 1635 cm ⁻¹ . The Raman band around 1635 cm ⁻¹ is assigned to the C═O stretching vibrational mode. The vibration direction is the mode perpendicular to the molecular chain. Since Raman scattering is strongly obtained when the vibration direction of the molecular chain and the polarization direction of the incident light match, the scattering intensity of this vibration mode changes in correlation with the degree of orientation. By taking the ratio of the intensity in each polarization direction, it becomes a parameter for evaluating the degree of orientation. Based on the intensity of the Raman band (near 1440 cm ⁻¹ ) attributed to the CH bending vibration mode with small orientation anisotropy, the orientation parameter can be calculated according to the following formula.
Orientation parameter = (I _{1635 vertical} /I _{1440 vertical} )/(I _{1635 parallel} /I _{1440 parallel} )
I _{1635 vertical} : intensity of 1635 cm ^-1 Raman band with polarization arrangement (90 degree direction) perpendicular to resin flow I _{1440 vertical} : intensity of 1440 cm ^-1 Raman band with polarization arrangement (90 degree direction) perpendicular to resin flow I _{1635 parallel} : intensity of 1635 cm ^-1 Raman band with polarization arrangement parallel to resin flow (0 degree direction) I _{1440 parallel} : intensity of 1440 cm ^-1 Raman band with polarization arrangement (0 degree direction) parallel to resin flow

By taking the average value of the 12 orientation parameters measured at equal intervals in the thickness direction from the surface of the molded product, the average value of the orientation parameters measured at 12 locations at equal intervals in the thickness direction from the surface of the molded product is obtained. be able to.

The standard deviation of the orientation parameters measured at 12 points at equal intervals in the thickness direction from the surface of the molded product is calculated by the following formula using the average of the orientation parameters obtained (the average of the orientation parameters x _k at each point) x. can be done.
Formula 1) x = (1/12) Σx _k (k = 1 to 12)
Formula 2) V=(1/12)Σ(x _k −x) ² (k=1 to 12)
Formula 3) σ = √V
x: average of orientation parameters at 12 locations x _k : orientation parameter at each location V: variance of orientation parameter σ: standard deviation.

The cooling crystallization temperature and melting point of the crystalline resin composition in the present invention can be obtained by the following methods. First, using a differential scanning calorimeter (DSC-7 manufactured by PerkinElmer), two-point calibration (indium and lead) and baseline correction are performed. A sample weighing 8 to 10 mg was heated at a temperature increase rate of 20 ° C./min and held at a temperature 15 ° C. higher than the maximum value of the melting curve for 1 minute, and then at a temperature decrease rate of 20 ° C./min. The crystallization exothermic peak temperature observed when cooled to 30° C. is defined as the cooling crystallization temperature. Further, after holding at 30° C. for 1 minute, the second heating step is performed at a rate of 20° C./min in the same manner as the first heating step. The melting endothermic peak temperature observed in this second heating step is taken as the melting point.

The crystalline resin composition used in the method for producing a molded article of the present invention is a resin composition containing at least one crystalline resin.

The crystalline resin composition of the present invention is preferably a crystalline resin composition in which 0 to 50 parts by weight of other components other than the crystalline resin are blended with 100 parts by weight of the crystalline resin. If the amount of other components exceeds 50 parts by weight, the proportion of the crystalline resin in the entire resin composition is reduced, which is undesirable because the heat resistance and chemical resistance are lowered. Alternatively, the crystalline resin alone may be one that does not contain other components.

In the present invention, the crystalline resin refers to a resin in which 5 J/g or more of heat of crystal fusion is observed when the temperature is raised from room temperature at a rate of 20° C./min using a differential scanning calorimeter (DSC). Polyolefin resins such as polyamide resin, polyester resin, polyphenylene sulfide resin, polypropylene resin, polyetheretherketone resin, polylactic acid resin, polyethylene resin, polymethylpentene resin, syndiotactic polystyrene resin, polyvinyl alcohol resin, polychloride Vinylidene resin, polyacetal resin, polyethylene tetrafluoride resin, crystalline polyimide resin, polyetherketone resin, polyketone resin and the like can be mentioned.

Polyamide resins, polyester resins, polyphenylene sulfide resins, polypropylene resins, and polyetheretherketone resins are preferably used among the above crystalline resins.

The above-mentioned polyamide resin is a resin composed of a polymer having an amide bond, and is mainly composed of amino acids, lactams or diamines and dicarboxylic acids. Representative examples of raw materials thereof include amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and para-aminomethylbenzoic acid; lactams such as ε-caprolactam and ω-laurolactam; methylenediamine, hexamethylenediamine, 2-methylpentamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4-/2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, meta-xylene Diamine, paraxylylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis(4 -aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminopropyl)piperazine, aminoethylpiperazine, and other aliphatic and alicyclic , aromatic diamines, and adipic acid, spelic acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium Aliphatic, cycloaliphatic, aromatic dicarboxylic acids such as sulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, etc., and in the present invention polyamide homopolymers or copolymers derived from these raw materials, respectively. They can be used singly or in the form of mixtures. Two or more of such polyamide resins may be blended.

Specific examples of particularly useful polyamide resins in the present invention include polycaproamide (polyamide 6), polyhexamethylene adipamide (polyamide 66), polypentamethylene adipamide (polyamide 56), and polytetramethylene. Adipamide (Polyamide 46), Polyhexamethylene Sebacamide (Polyamide 610), Polypentamethylene Sebacamide (Polyamide 510), Polyhexamethylene Dodecamide (Polyamide 612), Polyundecaneamide (Polyamide 11), Polydodecane amide (polyamide 12), polycaproamide/polyhexamethylene terephthalamide copolymer (polyamide 6/6T), polyhexamethylene adipamide/polyhexamethylene terephthalamide copolymer (polyamide 66/6T), polyhexamethylene adipamide/ Polyhexamethylene isophthalamide copolymer (polyamide 66/6I), polyhexamethylene adipamide/polyhexamethylene isophthalamide/polycaproamide copolymer (polyamide 66/6I/6), polyhexamethylene terephthalamide/polyhexamethylene isophthalamide copolymer (polyamide 6T/6I), polyhexamethylene terephthalamide/polydodecanamide copolymer (polyamide 6T/12), polyhexamethylene adipamide/polyhexamethylene terephthalamide/polyhexamethylene isophthalamide copolymer (polyamide 66/6T/ 6I), polyxylylene adipamide (polyamide MXD6), polyhexamethylene terephthalamide/poly-2-methylpentamethylene terephthalamide copolymer (polyamide 6T/M5T), polyhexamethylene terephthalamide/polypentamethylene terephthalamide copolymer ( polyamide 6T/5T) and mixtures or copolymers thereof.

Particularly preferred examples include polyamide 6 resin, polyamide 66 resin, polyamide 610 resin, polyamide 11 resin, polyamide 12 resin, polyamide 6/66 copolymer and polyamide 6/12 copolymer. Polyamide 6 resin and polyamide 610 resin are particularly preferred. Furthermore, it is practically suitable to use these polyamide resins as a mixture.

The degree of polymerization of these polyamide resins is not particularly limited, and the relative viscosity measured at 25° C. in a 98% concentrated sulfuric acid solution having a concentration of 0.01 g/ml of the polyamide resin is preferably in the range of 1.5 to 7.0. A polyamide resin having a relative viscosity of 1.8 to 6.0 is particularly preferred. When the relative viscosity is within the preferred range described above, the crystalline resin composition of the present invention can easily exhibit excellent toughness, and the melt viscosity of the crystalline resin composition is moderate, so that a molded article can be molded. is easy.

Examples of the polyester resin include polymers or copolymers obtained by a condensation reaction of a dicarboxylic acid (or an ester-forming derivative thereof) and a diol (or an ester-forming derivative thereof) as main components, or mixtures thereof. be done.

Examples of the dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, bis(p-carboxyphenyl)methane, anthracenedicarboxylic acid, and 4,4'-diphenyl ether dicarboxylic acid. acids, aromatic dicarboxylic acids such as 5-sodium sulfoisophthalic acid, aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid and dodecanedioic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, etc. and alicyclic dicarboxylic acids of and ester-forming derivatives thereof. Aliphatic glycols having 2 to 20 carbon atoms as diol components, namely ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol and decamethylene glycol. , cyclohexanedimethanol, cyclohexanediol, or long-chain glycols having a molecular weight of 400 to 6,000, such as polyethylene glycol, poly-1,3-propylene glycol, polytetramethylene glycol, and ester-forming derivatives thereof. .

Preferred examples of these polymers or copolymers include polybutylene terephthalate, polybutylene (terephthalate/isophthalate), polybutylene (terephthalate/adipate), polybutylene (terephthalate/sebacate), polybutylene (terephthalate/decanedicarboxylate), Polybutylene naphthalate, polyethylene terephthalate, polyethylene (terephthalate/isophthalate), polyethylene (terephthalate/adipate), polyethylene (terephthalate/5-sodium sulfoisophthalate), polybutylene (terephthalate/5-sodium sulfoisophthalate), polyethylene Naphthalate, polycyclohexanedimethylene terephthalate and the like, polybutylene terephthalate, polybutylene (terephthalate/adipate), polybutylene (terephthalate/decane dicarboxylate), polybutylene naphthalate, Particularly preferred are polyethylene terephthalate, polyethylene (terephthalate/adipate), polyethylene naphthalate, polycyclohexanedimethylene terephthalate, and most preferred are polyethylene terephthalate and polybutylene terephthalate.

Further, these polyester resins preferably have an intrinsic viscosity of 0.36 to 1.60 dl/g when an o-chlorophenol solution is measured at 25°C. In particular, those in the range of 0.52 to 1.35 dl/g are suitable from the viewpoint of mechanical properties and moldability.

As the polyphenylene sulfide resin, a polymer having a repeating unit represented by the following structural formula can be preferably used.

From the viewpoint of heat resistance, a polymer containing 70 mol % or more, more preferably 90 mol % or more of repeating units represented by the above structural formula is preferable. About less than 30 mol % of the repeating units of the polyphenylene sulfide resin may be composed of repeating units having any of the following structures. Among them, p-phenylene sulfide/m-phenylene sulfide copolymers (m-phenylene sulfide units of 20% or less) are preferably used because they have both moldability and barrier properties.

A polyphenylene sulfide resin can be produced in a high yield by recovering and post-treating a polyphenylene sulfide resin obtained by reacting a polyhalogen aromatic compound and a sulfidating agent in a polar organic solvent. Specifically, a method for obtaining a polymer with a relatively small molecular weight described in JP-B-45-3368, or a relatively molecular weight described in JP-B-52-12240 and JP-A-61-7332. It can also be produced by a method for obtaining a polymer having a large . Crosslinking/high molecular weight polyphenylene sulfide resin obtained by the above method by heating in air, heat treatment in inert gas atmosphere such as nitrogen or under reduced pressure, washing with organic solvent, hot water, acid aqueous solution, etc., acid anhydride It can also be used after being subjected to various treatments such as activation with a functional group-containing compound such as a compound, amine, isocyanate, or functional group-containing disulfide compound.

The melt flow rate (MFR) of the polyphenylene sulfide resin is preferably 20-1000 g/10 minutes. When the MFR is 20 g/10 minutes or more, the fluidity and injection moldability are excellent, and when it is 1000 g/10 minutes or less, the tensile elongation at break is high, which is preferable.

The melt flow rate (MFR) of the polyphenylene sulfide resin in the present invention is a value calculated by the method shown below. According to ASTM-D1238, 10 g of polyphenylene sulfide resin is retained at 315.5 ° C. for 5 minutes using a melt indexer manufactured by Toyo Seiki Co., Ltd., and then a load of 5 kg is applied for an arbitrary time. The amount of polyphenylene sulfide resin coming out of the comb is measured, and the melt flow rate is calculated.

The above-mentioned polypropylene resin is generally used as a molding material. Examples include polypropylene homopolymer, random or block copolymer of propylene and ethylene and/or α-olefin, such as ethylene-propylene random copolymer. Coalescing, ethylene-propylene block copolymers, and the like can be used. In the case of polypropylene homopolymer, isotactic, atactic, syndiotactic, etc. can all be used. This polypropylene resin may be used alone or in combination of two or more.

Polypropylene resins are homopolymers or copolymers of propylene, including unmodified ones and modified ones.

Examples of unmodified polypropylene resins include propylene homopolymers and copolymers of propylene with α-olefins, conjugated dienes, non-conjugated dienes, and the like. As the α-olefin, α-olefins having 2 to 12 carbon atoms other than propylene are preferable, such as ethylene, 1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, 3-methyl-1 -pentene, 4-methyl-1-hexene, 4,4 dimethyl-1-hexene, 1-nonene, 1-octene, 1-heptene, 1-hexene, 1-decene, 1-undecene, 1-dodecene and the like. be done. Examples of conjugated dienes and non-conjugated dienes include butadiene, ethylidenenorbornene, dicyclopentadiene, 1,5-hexadiene and the like. You may use 2 or more types of these. Examples of the skeleton structure of the unmodified polypropylene resin include propylene homopolymers, random or block copolymers of propylene and the other monomers, and copolymers of other thermoplastic monomers. can. Suitable examples include polypropylene, ethylene/propylene copolymer, propylene/1-butene copolymer, and ethylene/propylene/1-butene copolymer.

The modified polypropylene resin is preferably an acid-modified polypropylene resin, which is a polypropylene resin having carboxylic acid and/or its salt groups bonded to the polymer chain. The above acid-modified polypropylene resin can be obtained by various methods, for example, an unmodified polypropylene resin, a monomer having a carboxylic can be obtained by graft polymerizing a monomer having a carboxylic acid ester which is either unsaponified or unsaponified. Examples of monomers having a neutralized or non-neutralized carboxylic acid group and monomers having a saponified or non-saponified carboxylic acid ester group include, for example, ethylene Examples include unsaturated carboxylic acids and anhydrides thereof, esters thereof, and compounds having an unsaturated vinyl group other than olefins.

Examples of polyether ether ketone resins include those obtained by polycondensation of dihalogenobenzophenone and hydroquinone. Examples of commercially available polyether ether ketone resins include "Victrex PEEK" (trade name) manufactured by Victrex MC Co., Ltd., and the like.

A filler is preferably added to the crystalline resin composition used in the method for producing a molded article of the present invention. By blending a filler, it is possible to obtain a molded article with improved mechanical strength, flame retardancy, and heat distortion temperature.

The filler may be a fibrous filler or a non-fibrous filler, or may be used in combination with a fibrous filler and a non-fibrous filler. Examples of fibrous fillers include glass fiber, milled glass fiber, carbon fiber, potassium titanate whisker, zinc oxide whisker, aluminum borate whisker, aramid fiber, alumina fiber, silicon carbide fiber, ceramic fiber, asbestos fiber, gypsum. fibers, metal fibers and the like. Examples of non-fibrous fillers include wollastonite, zeolite, sericite, kaolin, mica, clay, pyrophyllite, bentonite, asbestos, talc, silicates such as alumina silicate; alumina, silicon oxide, magnesium oxide, oxide Metal oxides such as zirconium, titanium oxide and iron oxide; Metal carbonates such as calcium carbonate, magnesium carbonate and dolomite; Metal sulfates such as calcium sulfate and barium sulfate; metal hydroxides; glass beads, ceramic beads, boron nitride and silicon carbide; They may be hollow. Further, it is preferable to pretreat these fibrous and/or non-fibrous fillers with a coupling agent in order to obtain better mechanical properties. Examples of coupling agents include isocyanate-based compounds, organic silane-based compounds, organic titanate-based compounds, organic borane-based compounds, and epoxy compounds.

The crystalline resin composition used in the method for producing a molded article of the present invention may further contain various amorphous resins and various additives within a range that does not impair the object of the present invention.

Here, the amorphous resin refers to a resin having a crystal melting heat quantity of less than 5 J/g when the temperature is raised from room temperature at a rate of 20° C./min in a differential scanning calorimeter (DSC). Examples thereof include polycarbonate resins, polyphenylene oxide resins, polysulfone resins, polyetherimide resins, polyethersulfone resins, polymethyl methacrylate resins, styrene resins such as polystyrene resins and ABS resins.

Various additives include, for example, crystal nucleating agents, coloring inhibitors, antioxidants such as hindered phenols and hindered amines, release agents such as ethylenebisstearylamide, higher fatty acid esters, and amide waxes, plasticizers, heat Stabilizers, lubricants, UV inhibitors, colorants, flame retardants, foaming agents and the like.

Molded articles obtained by the manufacturing method of the molded article of the present invention can be used for connectors, coils, sensors, LED lamps, sockets, resistors, relay cases, small switches, coil bobbins, capacitors, variable capacitors, etc. Cases, optical pickups, oscillators, various terminal boards, transformers, plugs, printed circuit boards, tuners, speakers, microphones, headphones, small motors, magnetic head bases, power modules, semiconductors, liquid crystals, FDD carriages, FDD chassis, motor brushes In addition to being suitable for electronic parts such as holders, parabolic antennas, and computer-related parts, it is also suitable for generators, motors, transformers, current transformers, voltage regulators, rectifiers, inverters, relays, power contacts, and switches. , circuit breakers, knife switches, multi-pole rods, electrical equipment parts such as cabinets, VTR parts, TV parts, irons, hair dryers, rice cooker parts, microwave oven parts, audio parts, audio laser discs (registered trademark) )・Compact discs, DVD and other audio and video equipment parts, lighting parts, refrigerator parts, air conditioner parts, typewriter parts, word processor parts, etc.; , Facsimile-related parts, Copier-related parts, Cleaning jigs, Motor parts, Writers, Machine-related parts represented by typewriters: Microscopes, Binoculars, Cameras, Clocks and other optical instruments, Precision machinery-related parts Alternator terminals, alternator connectors, IC regulators, potentiometer bases for light dimmers, various valves such as exhaust gas valves, fuel-related, cooling systems, brake systems, wiper systems, exhaust systems, intake systems, various pipes, hoses, tubes, air Intake nozzle snorkel, intake manifold, fuel pump, engine coolant joint, carburetor main body, carburetor spacer, exhaust gas sensor, coolant sensor, oil temperature sensor, brake pad wear sensor, throttle position sensor, crankshaft position sensor, air flow Meters, brake pad wear sensors, battery peripherals, thermostat bases for air conditioners, hot air flow control valves for heating, brush holders for radiator motors, water pump impellers, turbine vanes, wipers Motor-related parts, dust tributors, starter switches, starter relays, wire harnesses for transmissions, window washer nozzles, air conditioner panel switch boards, coils for fuel-related electromagnetic valves, wire harness connectors, SMJ connectors, PCB connectors, door grommet connectors, fuses connectors, horn terminals, electric component insulation plates, step motor rotors, lamp sockets, lamp reflectors, lamp housings, brake pistons, solenoid bobbins, engine oil filters, ignition device cases, torque control levers, safety belt parts, Register blades, washer levers, window regulator handles, knobs for window regulator handles, passing light levers, sun visor brackets, instrument panels, airbag peripherals, door pads, pillars, console boxes, various motor housings, roof rails, fenders, garnishes, Bumpers, door panels, roof panels, hood panels, trunk lids, door mirror stays, spoilers, hood louvers, wheel covers, wheel caps, grille apron cover frames, lamp bezels, door handles, door moldings, rear finishers, wipers, etc. It is suitably used for parts and the like.

EXAMPLES Hereinafter, the effects of the present invention will be described more specifically with reference to examples. In addition, the present invention is not limited to the following examples. Evaluation in each example and comparative example was performed by the following method.

(1) Temperature-lowering crystallization temperature of the crystalline resin composition For the resin composition pellets obtained in each example and comparative example, using a differential scanning calorimeter (DSC-7 manufactured by PerkinElmer), two-point calibration (indium , lead), after performing baseline correction, weigh 8 to 10 mg of the sample, and heat the sample at a heating rate of 20 ° C./min. After holding at the high temperature for 1 minute, it was cooled to 30°C at a cooling rate of 20°C/min. The crystallization exothermic peak temperature observed in this cooling step was taken as the cooling crystallization temperature.

(2) Melting point of the crystalline resin composition For the resin composition pellets obtained in each example and comparative example, using a differential scanning calorimeter (PerkinElmer DSC-7), two-point calibration (indium, lead) , After performing baseline correction, 8 to 10 mg of the sample was weighed, and the sample was heated at a heating rate of 20 ° C./min at a temperature 15 ° C. higher than the maximum value of the melting curve obtained. After being held for 1 minute, it was cooled to 30°C at a temperature drop rate of 20°C/min. Furthermore, after holding at 30° C. for 1 minute, the second heating step was performed at a rate of 20° C./min in the same manner as the first heating step. The melting endothermic peak temperature observed in this second heating step was taken as the melting point.

(3) Toughness (tensile elongation at break)
The pellets obtained in each example and comparative example are injection molded according to the method and conditions shown in the examples and comparative examples, and a single-gate mold is used to perform a 1A type multipurpose test in accordance with ISO527-1:2012. A piece was made. This multi-purpose test piece was subjected to a tensile test at a tensile speed of 50 mm/min under room temperature conditions using a precision universal testing machine AG-20kNX (manufactured by Shimadzu Corporation) according to ISO527-1:2012 to measure the tensile elongation at break.

(4) Evaluation of burrs The pellets obtained in each example and comparative example are injection molded according to the method and conditions shown in the examples and comparative examples, using a single gate mold and conforming to ISO527-1:2012. The presence or absence of burrs was visually confirmed when the type 1A multi-purpose test piece was produced.

(5) Weld characteristics The pellets obtained in each example and comparative example are injection molded by the method shown in the examples and comparative examples, and a double gate mold is used to perform 1A conforming to ISO527-1:2012. A mold multi-purpose weld specimen was molded. A weld test piece is a test piece having a weld portion formed in the center thereof. Also, a single-gate mold was used to mold 1A type multi-purpose test specimens conforming to ISO527-1:2012. A tensile test was performed on each of the five test pieces obtained under the conditions of a distance between fulcrums of 114 mm, a tensile speed of 10 mm/min, and a temperature of 23° C. to evaluate the tensile strength. The average value of five measurements was taken as the tensile strength, and the weld portion tensile strength retention rate was calculated from the obtained tensile strength results. A higher weld portion tensile strength retention rate means better weld properties (weld tensile properties).
Weld part tensile strength retention rate = (tensile strength measured with 1A type multi-purpose weld test piece conforming to ISO527-1:2012 obtained using a double gate mold) / (single gate mold can be used) ISO527-1: Tensile strength measured with type 1A multi-purpose test piece in accordance with 2012) × 100

Raw materials and abbreviations used in Examples and Comparative Examples are shown below.
Polyamide 6 resin: manufactured by Toray Industries, Inc. (relative viscosity of 2.70 at 25°C in a 98% concentrated sulfuric acid solution with a resin concentration of 0.01 g/ml)
Polybutylene terephthalate resin: manufactured by Toray Industries, Inc. (weight average molecular weight 18,000)
Polyethylene terephthalate resin: manufactured by Toray Industries, Inc. (weight average molecular weight: 19,000)
Polyphenylene sulfide resin: manufactured by Toray Industries, Inc. (MFR 200 g/10 min (315.5°C, 5 kg load))
Polypropylene resin: Prime Polymer Co., Ltd. trade name ““Prime Polypro” J108M”
Polyether ether ketone resin: Product name “VICTOREX PEEK” 150P manufactured by VICTREX
Polycarbonate resin: Idemitsu Kosan Co., Ltd. product name ““Taflon” A1900”
Impact resistant material: Mitsui Chemicals, Inc., trade name “Tafmer” MH7020 (maleic anhydride-modified ethylene/1-butene copolymer)
Glass fiber: trade name “T249H” manufactured by Nippon Electric Glass Co., Ltd. (fiber diameter: 10.5 μm, fiber length: 3 mm, surface-treated with a silane coupling agent)
Carbon fiber: Toray Industries, Inc. Product name “Torayca” T700
Talc: Product name “LMS300” manufactured by Fuji Talc Industry Co., Ltd.

[Examples 1 to 11, Comparative Examples 2 to 3]
The raw materials shown in Tables 1 and 2 were set to the cylinder temperatures shown in Tables 1 and 2, the screw arrangement was provided with two kneading zones, and the screw rotation speed was 150 rpm. TEX30α-35BW-7V) (L / D = 45 (where L is the length from the raw material supply port to the discharge port, and D is the diameter of the screw))) and melt-kneaded, After extruding from the die, the gut was passed through a cooling bath filled with water controlled at 10° C. for 15 seconds to rapidly cool and fix the structure, and then pelletized with a strand cutter to obtain pellets. Using the obtained pellets, the mold temperature was raised to the mold temperature shown in Tables 1 and 2 by heater heating in a 75-ton injection molding machine set to the cylinder temperature shown in Tables 1 and 2.

The resin is injected into the mold (injection process), and immediately after injection, the mold temperature shown in Tables 1 and 2 is cooled to 80°C by water cooling (cooling time: 30 seconds). A type 1A multi-purpose test piece conforming to ISO527-1:2012 and a double gate type 1A multi-purpose weld test piece conforming to ISO527-1:2012 were molded. Tables 1 and 2 show the results of evaluation of the obtained molded articles by the method described above.

The molded article obtained in Example 1 had an average orientation parameter of 0.99 and a standard deviation of the orientation parameter of 0.03 measured at 12 points equally spaced in the thickness direction from the surface of the molded article. It was good because it was small and the variation in orientation was small.

[Comparative Examples 1 and 4 to 13]
The raw material shown in Table 2 was set to the cylinder temperature shown in Table 2, the screw arrangement was provided with two kneading zones, and the screw rotation speed was 150 rpm. 7V) (L / D = 45 (where L is the length from the raw material supply port to the discharge port, and D is the diameter of the screw))), melt-kneaded, and discharged from the die. The gut was passed through a cooling bath filled with water adjusted to 10° C. for 15 seconds to rapidly cool and fix the structure, and then pelletized with a strand cutter to obtain pellets. Using a 75-ton injection molding machine set to the cylinder temperature shown in Table 2, the obtained pellets were injected into a mold whose mold temperature was adjusted to 80 ° C. with hot water, and a single gate ISO 527 -1:2012 compliant Type 1A multi-purpose test specimens and double gate ISO 527-1:2012 compliant Type 1A multi-purpose weld specimens were molded. Table 2 shows the results of evaluating the obtained molded article by the method described above.

The molded article obtained from Comparative Example 1 had an average orientation parameter of 1.26 measured at 12 points in the thickness direction from the surface of the molded article, a standard deviation of the orientation parameter of 0.29, and a residual strain of large, and the variation in orientation was large.

The molded article obtained from Comparative Example 2 had an average orientation parameter of 1.22 and a standard deviation of the orientation parameter of 0.25, measured at 12 points equally spaced in the thickness direction of the molded article, and had a large residual strain. , the orientation variation was large.

From the above results, a crystalline resin composition containing at least one kind of crystalline resin was prepared so that the surface temperature of the cavity of the mold was higher than the cooling crystallization temperature and lower than the melting point of the crystalline resin composition. After the injection process is completed, the surface temperature of the mold cavity is cooled to below the crystallization temperature. Residual strain is suppressed and toughness is greatly improved. It was also found that a molded article having excellent weld properties was obtained.

INDUSTRIAL APPLICABILITY The manufacturing method of the present invention is extremely useful because it can obtain a molded product made of a crystalline resin composition that suppresses residual strain, greatly improves toughness, and has excellent weld properties.

Claims (3)

A crystalline resin composition containing at least one kind of crystalline resin is heated to a mold cavity surface temperature higher than the cooling crystallization temperature and lower than the melting point of the crystalline resin composition. A method for producing a molded product, characterized by performing heat and cool molding, in which an injection step is performed, and after the injection step, the surface temperature of the mold cavity is cooled to a temperature-lowering crystallization temperature or less of the crystalline resin composition. 2. The method for producing a molded article according to claim 1, wherein the crystalline resin is at least one selected from polyamide resin, polyester resin, polyphenylene sulfide resin, polypropylene resin, and polyetheretherketone resin. 3. The method for producing a molded article according to claim 1, wherein the crystalline resin composition contains a filler.