KR102203684B1 - Composite sheet - Google Patents

Abstract

The present invention relates to a composite sheet having remarkably improved physical properties such as impact resistance and scratch resistance as well as optical properties such as excellent transparency.

Description

Composite sheet{COMPOSITE SHEET}

The present invention relates to a composite sheet having remarkably improved physical properties such as impact resistance and scratch resistance as well as optical properties such as excellent transparency.

Recently, interest in replacing glass applied to various fields such as buildings, furniture, home appliances, kitchenware, heavy equipment, automobiles, etc. with transparent plastic is increasing.

In particular, in the automotive field, lightening vehicles and improving fuel economy accordingly have become a hot topic, and it is considered to replace glass with transparent plastic. In general, when the glass used in automobiles is replaced with plastic, the weight of the vehicle is reduced and the fuel economy of the vehicle is improved. In addition, when the glass used in the vehicle sunroof is replaced with plastic, the weight of the vehicle roof As is reduced, the center of gravity of the vehicle moves downward, and the low center of gravity gives the effect of improving stability when driving and rotating the vehicle.

As such transparent plastic glazing parts, polycarbonate resins with excellent durability are widely used, but polycarbonate resins can easily damage the surface and are vulnerable to impact resistance, low temperature impact, and chemical resistance, It has a problem of discoloration or deterioration of physical properties when exposed to.

On the other hand, in addition to the polycarbonate, development of transparent plastics using polymethylmethacrylate (PMMA) resin is also being made. In the case of the polymethyl methacrylate resin, it has excellent weather resistance, scratch resistance, and chemical resistance, but it has a problem that it is easily broken from external stimuli due to insufficient impact resistance, so it is limited to be applied alone as an automobile part requiring excellent physical properties. There is.

Accordingly, there is a need to develop a technology that can be applied to various fields as a transparent plastic glazing component by supplementing the disadvantages of such polycarbonate and polymethyl methacrylate resins.

An object of the present invention for solving the above problems is to ensure a stable long-term physical properties such as excellent weather resistance, scratch resistance, chemical resistance and transparency of polymethyl methacrylate resin, as well as to have a property synergistic effect, It is an object of the present invention to provide a composite sheet having remarkably improved physical properties by laminating a surface layer of a polymethyl methacrylate resin on both sides of the polymethyl methacrylate resin and an alloy of a polycarbonate resin as a base layer.

In addition, another object of the present invention is to provide a composite sheet having high light transmittance and excellent light diffusivity to effectively block external light while having excellent visibility and excellent anti-fogging properties.

In addition, another object of the present invention is to expand the range of applications including automotive exterior materials such as sunroof by satisfying various physical properties as a transparent plastic glazing component.

One aspect of the present invention for achieving the above object is a base layer comprising an alloy of a polymethyl methacrylate resin and a polycarbonate resin; It is a composite filter comprising; a surface layer formed on both sides of the base layer and comprising a polymethyl methacrylate resin.

In one aspect of the present invention, the alloy may include 5 to 50% by weight of a polymethyl methacrylate resin and 50 to 95% by weight of a polycarbonate resin.

In one aspect of the present invention, the surface layer may include light diffusion particles.

In one aspect of the present invention, the light-diffusing particles may have an average particle diameter of 0.001 to 20 μm.

In one aspect of the present invention, the light-diffusion particles may be any one or a mixture of two or more selected from calcium carbonate, barium sulfate, titanium dioxide, aluminum hydroxide, silica, talc, mica, magnesium oxide, and zinc oxide.

In one aspect of the present invention, the surface layer is an ethylene-acrylic acid copolymer, an ethylene-methacrylic acid copolymer, an ethylene-methyl acrylate copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-butyl acrylate copolymer, and an ethylene-vinyl It may be one further comprising any one or two or more ethylene copolymers selected from the group consisting of acetate copolymers.

Another aspect of the present invention relates to a method for manufacturing a composite sheet, and specifically, a resin composition for a base layer comprising an alloy of a polymethyl methacrylate resin and a polycarbonate resin and a surface layer resin composition comprising a polymethyl methacrylate resin Is laminated by coextrusion.

In one aspect of the present invention, the coextrusion may be performed at 200 to 350°C.

Another aspect of the present invention is an automobile exterior material comprising the above-described composite sheet.

In one aspect of the present invention, the vehicle exterior material may be any one selected from a sunroof, a windshield, a rear glass, a quarter glass, a front vent glass, and a rear vent glass.

The composite sheet according to the present invention has remarkably improved mechanical properties including weather resistance, impact resistance, scratch resistance and chemical resistance, and has the advantage of securing excellent durability.

In addition, as it has high light transmittance and excellent light diffusion, there is an advantage of securing cool openness and visibility while effectively blocking external light when applied to a glass substitute such as a sunroof.

Hereinafter, the composite sheet of the present invention will be described in detail. The present invention can be better understood by the following examples. The following examples are for illustrative purposes of the present invention, and are not intended to limit the scope of protection defined by the appended claims. In this case, the technical terms and scientific terms used have meanings commonly understood by those of ordinary skill in the technical field to which this invention belongs, unless otherwise defined.

The terms used in the description in the present invention are merely for effectively describing specific embodiments. In addition, the singular form used in the specification and the appended claims may be intended to include the plural form unless otherwise indicated in the context.

While the inventors of the present invention are intensifying research on plastic glazing products that replace glass with transparent plastics, polymethyl methacrylate resins on both sides of the substrate layer containing an alloy of polymethyl methacrylate resin and polycarbonate resin. By providing a composite sheet including a surface layer formed thereon, it was found that physical properties such as light diffusivity and impact resistance can be remarkably improved, and excellent physical properties can be maintained over a long period of time, thereby completing the present invention.

Hereinafter, the composite sheet according to the present invention will be described in detail.

One aspect of the present invention is a composite sheet comprising a base layer comprising an alloy of a polymethyl methacrylate resin and a polycarbonate resin, and a surface layer formed on both surfaces of the base layer and comprising a polymethyl methacrylate resin.

The composite sheet according to the present invention remarkably improves mechanical properties such as impact resistance by forming a surface layer containing polymethyl methacrylate resin on both sides of a base layer containing an alloy of polymethyl methacrylate resin and polycarbonate resin. I can make it. In addition, it has excellent weather resistance, scratch resistance, and chemical resistance, so that it can realize quality stability and reliability that can maintain excellent physical properties even when used for a long time.

The alloy of the polymethyl methacrylate resin and the polycarbonate resin according to the present invention means a blend of a polymethyl methacrylate resin and a polycarbonate resin.

By including the alloy as a substrate layer, it is possible to have more excellent durability and impact resistance, and to maintain excellent physical properties for a long time without deteriorating physical properties.

In one aspect of the present invention, the alloy may include 5 to 50% by weight of a polymethyl methacrylate resin and 50 to 95% by weight of a polycarbonate resin. Preferably containing 10 to 40% by weight of polymethyl methacrylate resin and 60 to 90% by weight of polycarbonate resin, more preferably 10 to 30% by weight of polymethyl methacrylate resin and 70 to 90% by weight of polycarbonate resin It may be, but is not limited thereto. When using an alloy of a polymethyl methacrylate resin and a polycarbonate resin in the above content range, the interfacial compatibility with the surface layer containing the polymethyl methacrylate resin is improved, so that adhesion is excellent, and impact resistance and durability are remarkably increased. Has the effect of being.

In one aspect of the present invention, the polymethyl methacrylate may be used without limitation, and may have a weight average molecular weight of 10,000 to 200,000 g/mol, preferably 50,000 to 150,000 g/mol. However, it is not limited thereto. When a polymethyl methacrylate resin having a weight average molecular weight in the above range is provided in an alloy state with a polycarbonate resin, the optical properties and molding processability of the composite sheet may be further improved.

In one aspect of the present invention, the polycarbonate resin may be used without limitation, used in the art, and may be a recycled polycarbonate resin obtained from a recycled resin, but is not limited thereto.

In one aspect of the present invention, the weight average molecular weight of the polycarbonate may be 10,000 to 500,000 g/mol, preferably 20,000 to 200,000 g/mol, but is not limited thereto. When a polycarbonate resin having a weight average molecular weight in the above range is provided in an alloy state with a polymethyl methacrylate resin, the mechanical properties and molding processability of the composite sheet may be further improved.

At this time, the weight average molecular weight was measured by dissolving the sample in tetrahydrofuran (THF) and using gel osmosis chromatography (GPC), and the analytical column was Styragel HR of WATERS, and the standard was polystyrene (PS). I did.

The composite sheet according to the present invention includes a surface layer comprising a polymethyl methacrylate resin formed on both sides of a base layer comprising an alloy of a polymethyl methacrylate resin and a polycarbonate resin. That is, the composite sheet according to the present invention has a structure in which a surface layer including a polymethyl methacrylate resin, a base layer including an alloy of a polymethyl methacrylate resin and a polycarbonate resin, and the surface layer are sequentially stacked. The composite sheet according to the present invention includes the surface layer and the base layer, and as it has a laminated configuration, excellent physical properties for a long period of time can be efficiently secured, and in particular, even in a wide temperature range including an extremely low temperature below zero. It has the effect of maintaining excellent mechanical properties and optical properties such as scratch resistance, impact resistance and chemical resistance.

In one aspect of the present invention, the polymethyl methacrylate resin in the surface layer is not significantly limited in weight average molecular weight within a range that does not impede the object of the present invention, but 10,000 to 200,000 g/mol, preferably 50,000 To 150,000 g/mol. When forming a surface layer containing a polymethyl methacrylate resin in the above range, it is possible to prevent a decrease in impact resistance due to long-term use and maintain excellent optical properties.

In one aspect of the present invention, the surface layer may include light diffusion particles. Since the surface layer including the polymethyl methacrylate resin includes light-diffusion particles, it has not only improved optical properties as a means of replacing glass, but also remarkably improving mechanical properties such as impact resistance.

In one aspect of the present invention, the light-diffusion particles may have an average particle diameter of 0.001 to 20 μm, preferably 0.01 to 15 μm, more preferably 0.1 to 10 μm, but are not limited thereto. Light-diffusing particles having an average particle diameter in the above range may have good dispersibility in the surface layer, and may be more preferred in terms of securing mechanical properties while implementing high light transmittance and light diffusivity, but is not limited thereto.

The light-diffusion particles may be included in 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight based on 100 parts by weight of the polymethyl methacrylate resin, but are not limited thereto.

In one aspect of the present invention, the kind of the light-diffusion particles is not greatly limited, but it is better to use inorganic particles than organic particles to achieve the object of the present invention, and calcium carbonate as the light-diffusion particles, Barium sulfate, titanium dioxide, aluminum hydroxide, silica, talc, mica, magnesium oxide, and a mixture of two or more selected from the group consisting of zinc oxide, but are not limited thereto.

The polymethyl methacrylate resin composition may include various additives, for example, antioxidants, ultraviolet stabilizers, flame retardants, and antistatic agents, etc., which are commonly used within a range that does not impair the object of the present invention, but is not limited thereto.

The UV stabilizer may be preferred in terms of not only preventing the deterioration of the properties of the resin itself and aging of the final molded product due to UV light, but also implementing a property synergistic effect according to a combination with other components in the composition.

The ultraviolet stabilizer may be any one or a mixture of two or more selected from benzotriazol-based, benzophenone-based, hindered amine light stabilizer (HALS)-based, and triazine-based, Preferably, it may be more effective to use a HALS-based compound, but is not limited thereto.

In one aspect of the present invention, the surface layer may further include an ethylene copolymer. As the ethylene copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, and ethylene-vinyl acetate copolymer. It may be to use any one or two or more ethylene copolymers selected from the group, and preferably, it is more effective to use an ethylene-ethyl acrylate copolymer, but is not limited thereto.

In one aspect of the present invention, the ethylene copolymer may be used in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the polymethyl methacrylate resin, but limited to the above range no. The ethylene copolymer in the above range has excellent compatibility with the polymethyl methacrylate resin, and can implement a more remarkably improved effect over the entire physical properties including scratch resistance and impact resistance.

In particular, as the surface layer containing the ethylene copolymer is used together with the substrate layer, the composite sheet has excellent anti-fog performance even in a harsh environment with very high humidity, as well as stably implementing optical properties, making it more effective. to be.

In one aspect of the present invention, the surface layer may further include an acrylic copolymer containing a carboxyl group derived from an acrylate-based monomer and an acrylic acid-based monomer.

In one aspect of the present invention, the carboxyl group-containing acrylic copolymer may be derived from an acrylate-based monomer and an acrylic acid-based monomer, and for specific examples, the acrylate-based monomer is methyl acrylate, ethyl acrylate, butyl acryl Rate, 2-ethylbutyl acrylate, 2-ethylhexyl methacrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, n-pentyl acrylate, vinyl acrylate, lauryl acrylate, ethyl methacrylate, butyl It may include any one or two or more selected from methacrylate, 2-ethylbutyl methacrylate, 2-ethylhexyl methacrylate and lauryl methacrylate, and the acrylic acid-based monomer is acrylic acid and methacrylic acid. It may include any one or two or more selected, but is not limited thereto.

In the case of including the carboxyl group-containing acrylic copolymer, the scratch resistance of the composite sheet may be further improved, and excellent physical properties may be maintained even at low temperatures. In addition, deterioration, cracking, and discoloration due to oxygen, heat, light, etc. can be prevented under practical environmental conditions, and excellent quality stability and reliability can be secured even when used for a long time.

The carboxyl group-containing acrylic copolymer may be used in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the polymethyl methacrylate resin, but is not limited thereto. Weather resistance and chemical resistance can be remarkably improved while securing optical properties within the above range.

In one aspect of the present invention, the thickness of the composite sheet may be appropriately adjusted depending on the field of application, but may be specifically 0.5 to 50 mm, more specifically 1.0 to 10 mm. In this case, the surface layer may have a thickness of 1 to 50%, preferably 2 to 20%, compared to the base layer. It is effective in terms of securing impact resistance and light diffusivity without deteriorating the desired physical properties in the thickness range as described above, but is not limited thereto.

In one aspect of the present invention, the surface layer is a UV stabilizer, an antistatic agent, an antioxidant, a heat stabilizer, a flame retardant, a light diffusing agent, a slip agent, a lubricant, a filler, a dye in order to secure physical properties such as improved weather resistance and chemical resistance. And any one or more additives selected from the group consisting of pigments may be further included. The types and contents of these additives may be appropriately adjusted at a level commonly used in this field, as necessary, but are not limited thereto.

The manufacturing method of the composite sheet according to the present invention is a base layer resin composition comprising an alloy of polymethyl methacrylate resin and polycarbonate resin and a surface layer resin composition comprising polymethyl methacrylate resin are coextruded and laminated.

In one aspect of the present invention, the co-extruder used in the co-extrusion can be extruded and coated in two or more layers of a resin composed of the same component or two or more different resins depending on the number or structure of the extruder. There is an advantage in that the sheet is easy to manufacture.

Specifically, a main extruder for extruding the base layer resin composition and two sub-extruders for extruding the surface layer resin composition may be used, and a composite sheet can be effectively manufactured by coextruding the composition through each extruder. .

In one aspect of the present invention, the base layer resin composition and the surface layer resin composition may be coextruded at 200 to 350°C, preferably 230 to 300°C, but are not limited to the above temperature range.

In one aspect of the present invention, the base layer and the surface layer resin composition may be coextruded using an extruder selected from a T-die, blown, and tubular type extruder, respectively, depending on the shape and use of the product. An extruder or a twin screw extruder or the like can be freely selected.

The composite sheet according to an aspect of the present invention has excellent mechanical and optical properties and can replace glass, so it can be applied to transparent plastic glazing products, and specifically applied as automobile exterior materials to secure long-term quality stability and reliability. can do.

In one aspect of the present invention, the vehicle exterior material may include a sunroof, a windshield, a rear glass, a quarter glass, a front vent glass, and a rear vent glass, but is not limited thereto.

In addition, the composite sheet according to an aspect of the present invention may be selected from parts used for agricultural machinery or heavy equipment other than automobiles. For example, the molded parts are door parts, spoilers, tank flaps, rocker panels, side panels, trims, fenders, lids, hoods, roofs, bumpers, fascias, grilles, wheel parts, frames. , Lamps, racks, or running boards may be selected, but is not limited thereto.

The composite sheet according to the present invention can realize remarkably improved optical properties, impact resistance, weather resistance, water resistance and chemical resistance, and can implement quality stability and reliability that can maintain excellent physical properties even when used for a long period of time. , For example, it can be applied to various fields such as buildings, furniture, home appliances and kitchenware.

The composite sheet according to the present invention will be described in more detail through the following examples. However, the following examples are only one reference for describing the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

Further, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. The terms used in the description herein are merely to effectively describe specific embodiments and are not intended to limit the invention.

In addition, the singular form used in the specification and the appended claims may be intended to include the plural form unless otherwise indicated in the context.

[Example 1]

After mixing 80% by weight of a polycarbonate resin having a weight average molecular weight of 50,000 g/mol and 20% by weight of a polymethyl methacrylate resin having a weight average molecular weight of 120,000 g/mol, it was put into a twin screw extruder at 260°C to form a pelletized alloy. Was prepared. The pelletized alloy was dried at 100° C. for 12 hours to prepare a base layer resin composition.

In addition, a surface layer resin composition was prepared by adding 1 part by weight of an ultraviolet stabilizer (HALS-based, Chimasofu 944 (CIBA-GEIGY)) to 100 parts by weight of polymethylmethacrylate having a weight average molecular weight of 120,000 g/mol. .

The base layer resin composition and the surface layer resin composition were added to each extruder, melted and kneaded, and then supplied to a feed block die to prepare a specimen having a laminated structure of a surface layer/substrate layer/surface layer. At this time, the extruder for extruding the base layer resin composition has a barrel diameter of 65 mm, a screw L/D=35, and a cylinder temperature of 260°C, and the extruder for extruding the surface layer resin composition has a barrel diameter of 32 mm and a screw L/ D=32, and the cylinder temperature was set to 270 degreeC. In addition, each layer was made to have a thickness of 500 μm/5,000 μm/500 μm.

[Example 2]

In the alloy of Example 1, it was carried out in the same manner as in Example 1, except that 95% by weight of polycarbonate resin and 5% by weight of polymethylmethacrylate were used.

[Example 3]

It was carried out in the same manner as in Example 1, except that 2 parts by weight of talc having an average particle diameter of 9 μm was further added to the surface layer resin composition of Example 1.

[Example 4]

2 parts by weight of talc having an average particle diameter of 9 μm and 5 parts by weight of ethylene-ethylacrylate (EAA; Ethylene-ethylacrylate, Dupont-Mitsui Polychem, EEA A703, ethylacrylate 25% by weight) were further added to the surface layer resin composition of Example 1 Except, it was carried out in the same manner as in Example 1.

[Example 5]

In the surface layer resin composition of Example 1, 2 parts by weight of talc having an average particle diameter of 9 μm, ethylene-ethyl acrylate (EAA; Ethylene-ethylacrylate, Dupont-Mitsui Polychem, EEA A703, ethylacrylate 25% by weight) 5 parts by weight and a weight average molecular weight It was carried out in the same manner as in Example 1, except that 2 parts by weight of the acrylic acid-acrylate copolymer of 180,000 g/mol was further added.

[Example 6]

In Example 1, in the laminated structure of the surface layer/substrate layer/surface layer, it was carried out in the same manner as in Example 1, except that the thickness of each layer was adjusted to 1,300 μm/5,000 μm/1,300 μm.

[Example 7]

It was carried out in the same manner as in Example 1, except that 2 parts by weight of talc having an average particle diameter of 25 μm was further added to the surface layer resin composition of Example 1.

[Comparative Example 1]

Melting the resin composition to which 1 part by weight of an ultraviolet stabilizer (HALS-based, Chimasofu 944 (CIBA-GEIGY)) was added to 100 parts by weight of polymethyl methacrylate (PMMA) having a weight average molecular weight of 120,000 g/mol, By kneading and extruding, a specimen having the same size as in Example 1 was prepared. At this time, extrusion was carried out at 270°C using a twin screw extruder having a diameter of 65 mm and screw L/D=35.

(evaluation)

(1) Impact resistance

The specimen was placed on the floor at room temperature (25°C) and a weight of 3 kg was dropped from a height of 0.5m to check whether or not cracks occurred. If no crack occurs more than 10 times, it is marked as ◎, if cracks occur in 7 to 9 times, ○, if cracks occur in 2 to 6 times, △, and if crack occurs in one time, it is marked as ×. In addition, after the specimen was left at -50°C for 4 hours, impact resistance was tested in the same manner as above.

(2) transmittance (%)

The transmittance of a specimen having a thickness of 2 mm was measured and compared using a haze meter (NIPPON DENSHOKU, YDP02-0D) according to ASTM D1003.

(3) light diffusivity

If one measures the acceptance angle 0 ° of the light transmittance I _0, acceptance angle 75 ° of the light transmittance I ₇₅ using a goniophotometric measurement is a value calculated then by the formula at least 90% ◎, is more than 85% ○, 75% If it exceeds 90%, it is marked as △, and if it is less than 75%, it is marked as x.

(Equation) Light diffusivity = (I ₇₅ /I ₀ ) × 100

(4) Izod impact strength (kgf·cm/cm ² )

It was measured using a notched specimen (1/4″) according to the regulations of ASTM D256.

(5) scratch resistance

BSP (Ball-type Scratch Profile) test was conducted. After applying a scratch of 20 mm to the surface of the specimen using a spherical metal tip with a diameter of 0.7 mm at a load of 1000 g and a speed of 75 mm/min, the profile of the applied scratch is measured through a contact surface profile analyzer (XP-1). By scanning using the tip of a metal stylus of 2 μm, the profile of the scratch was measured, and the Scratch width (μm) was calculated from this. As the measured scratch width decreases, the scratch resistance increases.

(6) Accelerated weatherability

As an experiment that can judge the durability of the material under outdoor use in a short period of time, a Sunshine Weather Meter (manufactured by Suga Test Instruments, 300 Sunshine Weather Meter) equipped with an open frame carbon arc lamp conforming to JIS K 7350-4 was used. It was observed whether the surface was discolored or cracked by accelerating the deterioration of the material for 5000 hours. If there is no change in the surface, it is marked as ◎, if discoloration or cracking occurs less than 2 (size within 0.25 cm2), ○, if 3 or more and less than 10 occur, △, and if exceeding 10, ×.

(7) Chemical resistance

After rubbing the surface of the specimen 10 times with a force of 5N using ethyl alcohol, it was observed whether discoloration or cracking of the surface occurred. If there is no change in the surface, it is marked as ◎, if discoloration or cracking occurs less than 2 (size within 0.25㎠), ○, if 3 or more and less than 10 occur, △, and if it exceeds 10, ×.

(8) Anti-fog: The specimen was placed 5 cm high from the water surface of the hot water bath maintained at 80°C, and the steam from the hot water bath was continuously irradiated, and the presence or absence of fogging 10 seconds after the irradiation was visually confirmed. . If no haze was observed at all, ◎, if clouding was not observed after only a moment after steam irradiation, ○, △ when slight haze was observed, and × when completely cloudy.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Comparative Example 1 Impact resistance
(25℃) ◎ ○ ◎ ◎ ◎ ○ ○ △ Impact resistance
(-50℃) ○ ○ ◎ ◎ ◎ ○ ○ × Transmittance (%) 87 85 92 94 95 84 86 89 Light diffusivity ○ ○ ◎ ◎ ◎ ○ ○ × Izod impact strength
(kgf·cm/cm ² ) 60 51 73 86 88 64 62 17 Scratch area (㎛) 289 296 225 210 182 306 256 384 Accelerated weathering ○ ○ ○ ◎ ◎ ○ ○ △ Chemical resistance ○ ○ ◎ ◎ ◎ ○ ◎ △ Anti-fogging ○ ○ ○ ◎ ◎ ○ ○ △

As can be seen in Table 1, the examples exhibited excellent impact resistance and scratch resistance across physical properties, and at the same time exhibited excellent performance in weather resistance, chemical resistance, and anti-fog resistance. In addition, it was confirmed that both light diffusivity and light transmittance, which are generally in a trade-off relationship, are excellent.

In particular, Examples 3 to 5 showed remarkable improvement in physical properties in light diffusion, low temperature impact resistance, and chemical resistance, and in the case of Examples 4 and 5 further comprising an ethylene-based copolymer, better accelerated weather resistance and anti-fogging properties It was confirmed that it could be secured.

In addition, as in Example 5, when the acrylic copolymer containing a carboxyl group was further included, it was confirmed that not only excellent light diffusivity was displayed, but also scratch resistance was further improved.

On the other hand, Comparative Example 1 was not only significantly lower in light diffusivity and impact resistance than in Examples, but also had poor physical properties in scratch resistance, accelerated weather resistance, chemical resistance and anti-fogging properties.

As described above, the present invention has been described by a limited embodiment, but this is only provided to help a more general understanding of the present invention. Anyone who has it can make various modifications and variations from these substrates.

Therefore, the spirit of the present invention is limited to the described embodiments and should not be defined, and all things that are equivalent or equivalent to the claims as well as the claims to be described later fall within the scope of the spirit of the present invention. .

Claims (10)

A base layer comprising an alloy of polymethyl methacrylate resin and polycarbonate resin;
A composite sheet comprising; a surface layer formed on both sides of the base layer and comprising a polymethyl methacrylate resin, an ethylene copolymer, an acrylic copolymer containing a carboxyl group, and light-diffusing particles,
The ethylene copolymer is composed of an ethylene-acrylic acid copolymer, an ethylene-methacrylic acid copolymer, an ethylene-methyl acrylate copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-butyl acrylate copolymer, and an ethylene-vinyl acetate copolymer. Any one selected from the group or a composite sheet of two or more. The method of claim 1,
The alloy is a composite sheet comprising 5 to 50% by weight of a polymethyl methacrylate resin and 50 to 95% by weight of a polycarbonate resin. delete The method of claim 1,
The light-diffusing particles are composite sheets having an average particle diameter of 0.001 to 20 μm. The method of claim 1,
The light-diffusion particles are any one or a mixture of two or more selected from calcium carbonate, barium sulfate, titanium dioxide, aluminum hydroxide, silica, talc, mica, magnesium oxide, and zinc oxide. delete By coextrusion of a base layer resin composition containing an alloy of polymethyl methacrylate resin and polycarbonate resin and a surface layer resin composition containing polymethyl methacrylate resin, ethylene copolymer, carboxyl group-containing acrylic copolymer and light diffusing particles. As a method of manufacturing a laminated composite sheet,
The ethylene copolymer is composed of an ethylene-acrylic acid copolymer, an ethylene-methacrylic acid copolymer, an ethylene-methyl acrylate copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-butyl acrylate copolymer, and an ethylene-vinyl acetate copolymer. Any one selected from the group or a method for producing a composite sheet that is two or more. The method of claim 7,
The co-extrusion is a method of manufacturing a composite sheet performed at 200 to 350 ℃. An automobile exterior material comprising the composite sheet of any one of claims 1, 2, 4 and 5. The method of claim 9,
The automotive exterior material is any one selected from a sunroof, a windshield, a rear glass, a quarter glass, a front vent glass, and a rear vent glass.