KR20200075340A - 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. The composite sheet includes a base layer and a surface layer.

Description

Composite sheet {COMPOSITE SHEET}

The present invention relates to a composite sheet having significantly 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, household appliances, kitchenware, heavy equipment, and automobiles with transparent plastics has increased.

Particularly, in the automobile field, it is considered to replace glass with transparent plastic as the weight reduction of the vehicle and the improvement of fuel efficiency are a hot topic. In general, when the glass applied to a car is replaced with plastic, the weight of the car is reduced to improve the fuel efficiency of the vehicle, and when the glass used in the sunroof of the car is replaced with plastic, the weight of the car roof As is decreased, the center of gravity of the vehicle moves downward, and the low center of gravity gives an effect of improving stability when driving and rotating the vehicle.

As such a transparent plastic glazing component, a polycarbonate resin having excellent durability is often used, but the surface of the polycarbonate resin can be easily damaged, and the impact resistance, low temperature impact resistance, and chemical resistance are weak and external for a long time. It has a problem of discoloration or deterioration of properties when exposed to.

Meanwhile, in addition to the polycarbonate, development of transparent plastics using polymethylmethacrylate (PMMA) resins has also been made. In the case of the polymethyl methacrylate resin, it has excellent weather resistance, scratch resistance, chemical resistance, etc., but lacks impact resistance, so it is easily broken from external stimuli, and it is difficult to apply alone as an automobile component 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 compensating for the disadvantages of the polycarbonate and polymethyl methacrylate resins.

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

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

In addition, another object of the present invention is to make it possible to broaden its application range including automotive exterior materials such as sunroof by satisfying various properties as transparent plastic glazing parts.

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 formed on both sides of the base layer, a surface filter comprising a polymethyl methacrylate resin; is a composite filter comprising a.

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

In one aspect of the present invention, the surface layer may include light diffusing 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 invention, the light-diffusing 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 ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methylacrylate copolymer, ethylene-ethylacrylate copolymer, ethylene-butylacrylate copolymer and ethylene-vinyl It may be to further include 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, specifically, a base layer resin composition comprising an alloy of a polymethyl methacrylate resin and a polycarbonate resin and a surface layer resin composition comprising a polymethyl methacrylate resin Is co-extruded and laminated.

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 automotive exterior material comprising the composite sheet described above.

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

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

In addition, as it has high light transmittance and excellent light diffusivity, it has an advantage of effectively blocking external light and securing a cool openness and visibility when applied to a glass replacement means 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. At this time, the technical terms and scientific terms to be used, unless otherwise defined, has a meaning commonly understood by those of ordinary skill in the art to which this invention belongs.

The terminology used in the description of the present invention is only to effectively describe a specific embodiment. 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.

The inventors of the present invention, while intensifying research on plastic glazing products that replace glass with transparent plastic, polymethyl methacrylate resins on both sides of the base layer comprising an alloy of polymethyl methacrylate resin and polycarbonate resin. By providing a composite sheet having a surface layer formed therein, the present invention was completed by discovering that it is possible to significantly improve physical properties such as light diffusion and impact resistance, as well as maintain excellent physical properties in the long term.

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 significantly improves mechanical properties such as impact resistance by forming a surface layer comprising polymethyl methacrylate resin on both sides of a base layer comprising an alloy of polymethyl methacrylate resin and polycarbonate resin I can do it. In addition, it has excellent weather resistance, scratch resistance and chemical resistance, so 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 that a polymethyl methacrylate resin and a polycarbonate resin are blended.

By including the alloy as a base layer, it can have better durability and impact resistance, and can maintain excellent physical properties for a long period of time without deteriorating physical properties.

In one embodiment of the present invention, the alloy may include 5 to 50% by weight of polymethyl methacrylate resin and 50 to 95% by weight of polycarbonate resin. Preferably 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 to provide excellent adhesion, significantly improve impact resistance and durability. It has an effect.

In one aspect of the present invention, the polymethyl methacrylate may be used without limitation used in the art, 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 a polycarbonate resin and an alloy state, optical properties and molding processability of the composite sheet may be further improved.

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

In one embodiment 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 a polymethyl methacrylate resin and an alloy, mechanical properties and molding processability of the composite sheet may be further improved.

At this time, the weight average molecular weight was measured using gel osmosis chromatography (GPC) by dissolving the sample in tetrahydrofuran (THF), and the analysis column was Styragel HR from WATERS, and the standard material was polystyrene (PS). 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 surface layer comprising a polymethyl methacrylate resin, a base layer comprising an alloy of a polymethyl methacrylate resin and a polycarbonate resin, and the surface layer sequentially stacked. The composite sheet according to the present invention includes the surface layer and the base layer, and as it has a laminated structure, it is possible to efficiently secure excellent physical properties for a long period of time, especially in a wide temperature range including extremely low temperatures below subzero. 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 limited to a large weight average molecular weight within a range that does not inhibit the desired purpose of the present invention, but 10,000 to 200,000 g/mol, preferably 50,000 To 150,000 g/mol. When forming the surface layer containing the polymethyl methacrylate resin in the above range, it is possible to prevent the degradation of impact resistance due to long-term use, it is possible to maintain excellent optical properties.

In one aspect of the present invention, the surface layer may include light diffusing particles. The surface layer containing the polymethyl methacrylate resin includes light-diffusing particles, and thus has a remarkable improvement effect of mechanical properties such as impact resistance as well as improved optical properties as a glass replacement means.

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

The light-diffusing particles may be included in an amount of 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 type of the light-diffusing particles is not greatly limited, but it is better to achieve the object of the present invention using inorganic particles rather than organic particles, and calcium carbonate as the light-diffusing particles, Barium sulfate, titanium dioxide, aluminum hydroxide, silica, talc, mica, magnesium oxide and zinc oxide may be any one or two or more mixtures selected from the group consisting of, but are not limited to.

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

The ultraviolet stabilizer may be preferred in terms of not only preventing the degradation of the properties of the resin itself due to ultraviolet rays and aging of the final molded product, but also realizing a synergistic effect according to combination with other components in the composition.

The UV stabilizer may include any one or two or more mixtures selected from benzotriazol, benzophenone, HALS (hindered amine light stabilizer) and triazine systems, 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, an ethylene-acrylic acid copolymer, an ethylene-methacrylic acid copolymer, an ethylene-methylacrylate copolymer, an ethylene-ethylacrylate copolymer, an ethylene-butylacrylate copolymer and an ethylene-vinyl acetate copolymer It may be to use any one or two or more ethylene copolymers selected from the group, preferably using an ethylene-ethyl acrylate copolymer is more effective, 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 is limited to the above range no. The ethylene copolymer in the above range is excellent in compatibility with the polymethyl methacrylate resin, and can realize a more remarkably improved effect over physical properties including scratch resistance and impact resistance.

Particularly, as the surface layer containing the ethylene copolymer is used together with the base layer, the anti-fog performance of the composite sheet is excellent even in a poor environment with very high humidity, and the optical properties can be stably implemented to be more effective. to be.

In one aspect of the present invention, the surface layer may further include an acrylate-based monomer and an acrylic copolymer containing a carboxyl group derived from 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 example, the acrylate-based monomer is methyl acrylate, ethyl acrylate, butyl acrylic Acrylate, 2-ethylbutyl acrylate, 2-ethylhexyl methacrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, n-pentyl acrylate, vinyl acrylate, lauryl acrylate, ethyl methacrylate, butyl Methacrylate, 2-ethyl butyl methacrylate, 2-ethylhexyl methacrylate, and lauryl methacrylate may include any one or two or more selected from, and the acrylic acid-based monomers in acrylic acid and methacrylic acid, etc. It may include any one or two or more selected, but is not limited thereto.

When the carboxyl group-containing acrylic copolymer is included, scratch resistance of the composite sheet can be further improved, and excellent properties can be maintained even at low temperatures. In addition, deterioration, cracking, and discoloration by oxygen, heat, light, etc. under practical environmental conditions can be prevented, and thus excellent quality stability and reliability can be secured even in long-term use.

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. Weatherability and chemical resistance can be remarkably improved while securing optical properties within the above range.

In one aspect of the present invention, the composite sheet may be appropriately adjusted in thickness depending on the application field, but may be specifically 0.5 to 50 mm, more specifically 1.0 to 10 mm. At this time, the surface layer may have a thickness of 1 to 50%, preferably 2 to 20%, compared to the base layer. Although effective in terms of securing impact resistance and light diffusion without deteriorating desired physical properties in the above-described thickness range, it 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 diffusion agent, a slip agent, a lubricant, a filler, and a dye in order to secure physical properties such as improved weatherability and chemical resistance And any one or more additives selected from the group consisting of pigments. The type and content of these additives may be appropriately adjusted at a level commonly used in this field, if necessary, but is not limited thereto.

The method for manufacturing a composite sheet according to the present invention is obtained by coextruding a base layer resin composition comprising an alloy of a polymethyl methacrylate resin and a polycarbonate resin and a surface layer resin composition comprising a polymethyl methacrylate resin.

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

Specifically, a main extruder extruding the base layer resin composition and two sub extruders extruding the surface layer resin composition may be used, and a composite sheet can be effectively produced 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 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, and may be single-axis depending on the shape and use of the product. An extruder or a twin-screw extruder 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 a transparent plastic glazing product, and specifically applied as an automotive exterior material to secure long-term quality stability and reliability can do.

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

In addition, the composite sheet according to an aspect of the present invention may be selected from parts used for transportation vehicles other than automobiles, agricultural machinery or heavy equipment. For example, the molded article may include door parts, spoilers, tank flaps, rocker panels, side panels, trims, fenders, leads, hoods, roofs, bumpers, fascias, grilles, wheel parts, frames , Lamp, rack or running board, 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 time, in addition to the transportation means , For example, it can be applied to various fields such as buildings, furniture, household appliances, and kitchenware.

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

In addition, 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 this invention belongs. The terms used in the description herein are for the purpose of effectively describing specific embodiments and are not intended to limit the present invention.

Also, 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, the mixture is put into a twin-screw extruder at 260°C to form pellets of alloy. Was prepared. The alloy in the pellet state was dried at 100° C. for 12 hours to prepare a resin composition for a base layer.

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

The base layer resin composition and the surface layer resin composition were introduced into each extruder, melted and kneaded, and then supplied to a feed block die to prepare a specimen having a layered structure of a surface layer/base layer/surface layer. At this time, the extruder extruding the base layer resin composition has a barrel diameter of 65 mm, the screw L/D=35, the cylinder temperature is 260°C, and the extruder extruding the surface layer resin composition has a barrel diameter of 32 mm, the screw L/ D=32, and the cylinder temperature was set to 270°C. In addition, each layer had 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 polymethyl methacrylate 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-ethyl acrylate (EAA; Ethylene-ethylacrylate, Dupont-Mitsui Polychem, EEA A703, ethylacrylate 25% by weight) were added to the surface layer resin composition of Example 1 It was carried out in the same manner as in Example 1 except for.

[Example 5]

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

[Example 6]

In Example 1, in the layered structure of the surface layer/base 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]

Melt the resin composition by adding 1 part by weight of an ultraviolet stabilizer (HALS system, Chimasofu 944 (CIBA-GEIGY)) to 100 parts by weight of polymethyl methacrylate (PMMA) having a weight average molecular weight of 120,000 g/mol, Kneading extrusion was performed to prepare specimens of the same size as in Example 1. At this time, extrusion was performed at 270°C using a twin-screw extruder having a diameter of 65 mm and a screw L/D=35.

(evaluation)

(1) Impact resistance

Placing the specimen at room temperature (25°C) on the floor and dropping the weight of 3kg from a height of 0.5m was performed once to check whether cracking occurred. If cracks do not occur more than 10 times, ◎, when cracks occur in 7 to 9 times, ○, when cracks occur in 2 to 6 times, and △, when cracks occur in 1 time, are denoted as ×. In addition, after the specimen was left at -50°C for 4 hours, the impact resistance was tested in the same manner as above.

(2) Transmittance (%)

According to the provisions of ASTM D1003, a haze meter (NIPPON DENSHOKU, YDP02-0D) was used to measure and compare the transmittance of a specimen having a thickness of 2 mm.

(3) Light diffusion

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 is less than 90%, it is indicated by Δ, and if it is less than 75%, x.

(Equation) Light diffusion rate = (I ₇₅ /I ₀ ) × 100

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

Measured using Notched Specimen (1/4″) according to ASTM D256.

(5) Scratch resistance

BSP (Ball-type Scratch Profile) test was performed. The surface of the specimen was subjected to a 20 mm length of scratch using a spherical metal tip of 0.7 mm diameter at a speed of 75 mm/min and a load of 1000 g, and then the profile of the applied scratch was diameter through a contact surface profile analyzer (XP-1). Scanning was performed using a tip of a 2 µm metal stylus to measure the profile of the scratch, from which a Scratch width (µm) was calculated. The scratch resistance increases as the measured scratch width decreases.

(6) Accelerated weathering

As an experiment that can judge the durability of the material under outdoor use in a short period of time, using a sunshine weather meter (made by Suga Test Instruments, 300 sunshine weather meter) equipped with an open frame carbon arc lamp conforming to JIS K 7350-4, It was observed whether the surface was discolored or cracked by promoting the deterioration of the material for 5000 hours. If there is no change on the surface, ◎, if discoloration or cracking occurs in 2 or less (sizes within 0.25 cm2) or less, △ when 3 or more and less than 10 occur, and × if more than 10 are indicated.

(7) Chemical resistance

Using ethyl alcohol, the surface of the specimen was rubbed by reciprocating 10 times with a force of 5N, and then it was observed whether discoloration or cracking of the surface occurred. If there is no change on the surface, ◎, if discoloration or cracking occurs in 2 or less (sizes within 0.25 cm2) or less, △ when 3 or more and less than 10 occur, and × if more than 10 are indicated.

(8) Anti-fog: The specimen was placed at a height of 5 cm from the 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 cloudiness after 10 seconds from irradiation was visually confirmed. . If no cloudiness was observed at all, ◎, after steam irradiation for a moment, after cloudiness was not observed, ○, if blurring was observed, △;

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 diffusion ○ ○ ◎ ◎ ◎ ○ ○ × Izod impact strength
(kgfcm/cm ² ) 60 51 73 86 88 64 62 17 Scratch area (㎛) 289 296 225 210 182 306 256 384 Accelerate weatherability ○ ○ ○ ◎ ◎ ○ ○ △ Chemical resistance ○ ○ ◎ ◎ ◎ ○ ◎ △ Antifogging ○ ○ ○ ◎ ◎ ○ ○ △

As can be seen in Table 1, the examples exhibited excellent impact resistance and scratch resistance throughout the physical properties, and also exhibited excellent performance in weather resistance, chemical resistance, and antifogging properties. In addition, it was confirmed that, in general, both light diffusion and light transmission in a trade-off relationship were excellent.

Particularly, Examples 3 to 5 showed remarkable physical property improvement in light diffusivity, low temperature impact resistance, and chemical resistance, and in Examples 4 and 5 further comprising an ethylene copolymer, better accelerated weatherability and antifogging properties It was confirmed that it can be secured.

In addition, when further comprising an acrylic copolymer containing a carboxyl group as in Example 5, it was confirmed that not only exhibits excellent light diffusivity but also scratch resistance is 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 terms of scratch resistance, accelerated weather resistance, chemical resistance, and antifogging properties.

As described above, the present invention has been described by a limited embodiment, but this is provided only to help a more comprehensive understanding of the present invention, and the present invention is not limited to the above embodiments, and general knowledge in the field to which the present invention pertains Various modifications and variations can be made by those who have this description.

Accordingly, the spirit of the present invention should not be limited to the described embodiments, and should not be determined, and all claims that are equivalent or equivalent to the scope of the claims as well as the claims described below belong to the scope of the spirit of the invention. .

Claims (10)

A base layer comprising an alloy of polymethyl methacrylate resin and polycarbonate resin;
It is formed on both sides of the base layer, a surface layer comprising a polymethyl methacrylate resin; containing composite sheet. According to claim 1,
The alloy is a composite sheet comprising 5 to 50% by weight of polymethyl methacrylate resin and 50 to 95% by weight of polycarbonate resin. According to claim 1,
The surface layer is a composite sheet comprising light-diffusing particles. According to claim 3,
The light-diffusing particles are composite sheets having an average particle diameter of 0.001 to 20 μm. According to claim 3,
The light-diffusing particles are composite sheets of any one or more mixtures selected from calcium carbonate, barium sulfate, titanium dioxide, aluminum hydroxide, silica, talc, mica, magnesium oxide and zinc oxide. According to claim 1,
The surface layer is from the group consisting of ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methylacrylate copolymer, ethylene-ethylacrylate copolymer, ethylene-butylacrylate copolymer and ethylene-vinyl acetate copolymer. A composite sheet further comprising any one or more ethylene copolymer selected. A method of manufacturing a composite sheet obtained by coextruding and laminating a base layer resin composition comprising an alloy of a polymethyl methacrylate resin and a polycarbonate resin and a surface layer resin composition comprising a polymethyl methacrylate resin. The method of claim 7,
The coextrusion method of manufacturing a composite sheet performed at 200 to 350 ℃. An automotive exterior material comprising the composite sheet of any one of claims 1 to 6. The method of claim 9,
The automotive exterior material is any one selected from sunroof, windshield, rear glass, quarter glass, front vent glass and rear vent glass.