TW378225B - Biaxially stretched polystyrene resin sheet - Google Patents

Abstract

Disclosed are a biaxially stretched polystyrene resin sheet obtained by biaxially stretching a resin composition comprising (A) a transparent polystyrene resin and (B) crosslinked polystyrene fine particles having an average particle size of 1 to 10 mu m in an amount of from 0.01 to 1 % by weight based on the resin composition or a resin composition comprising (A) a transparent polystyrene resin, (B) crosslinked polystyrene fine particles having an average particle size of 1 to 10 mu m in an amount of 0.006 to 0.06 % by weight based on the resin composition, and (C) a rubber modified polystyrene resin containing a diene rubber component having an average particle size of 0.1 to 3 mu m in such an amount that the diene rubber component concentration attributed to the rubber modified polystyrene resin is from 0.01 to 0.1 % by weight based on the resin composition. The polystyrene stretched sheets exhibit improved blocking resistance owing to fine unevenness uniformly formed on the surface thereof while retaining the transparency. Even when a number of the sheets or formings obtained therefrom are stacked, they are easily separated apart without blocking.

Description

A7 B7 Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs 5. Description of the invention L) 1 1 Field of invention 1 I This invention relates to a biaxially stretched polystyrene I with high transparency I | resin sheet which can be uniform The floor is coated with silicone oil f and when stacking ΛΛ. Sheets should be 1 1 闳 —ts * BX shows satisfactory anti-blocking when filming. Read back 1 1 side I invention-y background note 1 double Axially stretched polystyrene resin sheets have been widely used in food packaging because of their transparency and resistance to deformation. However, they have shown a strong tendency to be filled with A and g. It is also difficult to separate. Write this page 1 In order to overcome the problem of axillary adhesions, some people have proposed The particles are added to the poly- »··, and the ethylenic acid is shown in JP-A -50- 74649 (as used herein " JP-A, where the term 1 means" unexamined published Japanese patent " Application ") and adding silicone oil to the surface of the stretched polystyrene resin sheet as shown in JP-A-52-8080 1 | Show 0 The rubber particles of the styrene resin matrix will be biaxial Protruding from the surface of I 1 when stretched to improve the stretch sheet-V Anti-blocking 0 and rubber particles 1 1 will be St * »when biaxially stretched. The proportion of rubber protruding from the surface is almost 4 will not Constantly non-zero rubber added in order to ensure satisfactory anti-blocking properties. 1 easily leads to a decrease in transparency 0 In addition, as the rubber content increases 9 1 1 I The external W quality may be caused by the scorch or addition of rubber during long-term operation Then rub rubber 1 1 glue -½. Coking into resin composition It will lead to a bad sheet appearance 1 1 and cause sheet breakage | Some people have suggested to increase the rubber particle size (m diameter size) such as about 6-10 / X m to reduce the rubber content, but this will make the resulting biaxial The surface of the stretched sheet is roughened or reduced in gloss 1 1 Some people have also proposed that synthetic silicon dioxide (JP- B-6-856) be used. 1 1 This paper size applies to Chinese National Standard (CNS) A4 specifications ( 210X297 mm) -4-83. 3.10,000 A7. B7 V. Description of Invention (2) The word "JP-B" means "Japanese Patent Application Examined and Published" or silicon dioxide and styrene -Graft rubber combination (JP-B ^ 6-855) with polystyrene (please read the notes on the back before filling this page) Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs, Erqi + ig Silicon Society ShiM improves the blocking resistance of wood. However, the sheet has reduced physical properties due to silicon dioxide (refractive index: matrix (refers to emissivity · 1.55 ~ 1.59)) and gloss. In addition, it has poor wettability, which reduces its physical properties. There is no practicality. JP-B-47-2180 discloses a method for producing a base, a carboxyl group, an epoxy group, and a cis-butene, but it is applied to biaxial stretching for articles with excellent transparency. JP-B-55-7471 Disclosed is a product which provides an opaque, semi-transparent overview of the biaxially stretched invention disclosed by the present invention. The inventors have developed a resin with a matrix and fine particles of refractive index close to that of polystyrene resin. Biaxially stretched fine particles that are uniform and fine when stretched will not flatten and protrude when stretched. Results | Biaxially stretched silicone coating properties, no external biaxially stretched The stretched sheet protrudes on the surface, and in these systems, the difference in refractive index between the biaxial stretching (1.3 ~ 1.45) and the polystyrene resin makes the transparent silicon dioxide to polystyrene The vinyl matrix will come off the matrix. When the obtained sheet has a polymer film having a fine particle of at least one functional group selected from amine groups and dianhydride units, the polystyrene resin resin sheet cannot provide the resin composition in which the fine particle polymer is dispersed or delustered. Sheet, but cannot provide such as polystyrene resin sheet. The composition is a cross-linked styrene system containing a polystyrene resin as an olefin resin matrix, and can provide a transparent polystyrene resin sheet having a uniform and transparent surface. The fine styrene resin sheet formed on the surface of the stretched sheet has a modified metamorphic quality. Due to the added paper size, the Chinese National Standard (CNS) A4 specification (210 × 297 mm) 5 83 3.10,000 A7 B7 V. Description of the invention (3) The cracking and reduction of transparency that silicon or rubber coke tends to occur, and shows improved blocking resistance, even when many sheets are punched out, The pieces can also be easily separated. Therefore, an object of the present invention is to provide a biaxially stretched styrene resin sheet, which has an improved coating property of silicone oil and does not cause external deterioration and sheet cracking. Yet another object of the present invention is to provide a biaxially stretched styrene ethyl resin resin sheet, which can ensure the increase of blocking resistance and at the same time suppress the deterioration of the transparency of the sheet. When a stack of sheets is die-cut, each sheet The wood can be easily separated. Still another object of the present invention is to provide a method for manufacturing a biaxially stretched styrene resin sheet having the above-mentioned advantageous characteristics in the M-11 mode. 'The first specific example of the present invention relates to a biaxially stretched polystyrene resin sheet which is obtained by biaxially stretching a transparent polystyrene resin containing (A) and (B) from 0.01 based on the obtained resin composition. A resin composition having an amount of ~ 1 by weight I having a crosslinked polystyrene fine particle having an average particle size of 1 ~ 10 «m. Printed by the Consumers' Cooperative of the China Standards Bureau of the Ministry of Economic Affairs (please read the notes on the back before filling this page) The second specific example of the present invention is a biaxially stretched polystyrene resin sheet borrowed from biaxial stretching 1 contains (A) transparent polystyrene resin, (B) crosslinked polystyrene fine particles having an average particle size of 1 to 10 w ra and (C) contains 0.1 to 3 wm of an average particle size Diene rubber obtained by modifying the resin composition of a polystyrene resin. The rubber modified polystyrene resin is added so that the diene rubber concentration of the polystyrene resin attributed to the rubber modification is based on the obtained resin composition from 0.01 to 0.1 weight J! (1 0 0 PP m ~ ΙΟΟΟρριπ). K is added to the crosslinked polystyrene fine particles in an amount of 0.006 to 0.06 wt% (60 to 60 p pm) based on the resin composition. This paper size applies Chinese National Standard (CNS) A4 specification (21.0X 297 mm) _ δ-83. 3.10,000

A 4 / V indicates that the composition of the wedding ceremony is better than the equivalent of the aliphatic resin ethyl ester. Benzene SA has a weight of about 9 and a weight of one olefin, less benzene to benzene-containing alkane-containing lipids, and alkenyl ethyl ethyl benzene, such as poly's. Butyl phenyl ethyl propyl phenyl isopropyl p-alkane I a ene, ethene} phenenyl ethyl ethyl p-phenylene, butene triethyl p-phenylene or methylene p-ethyl or p-phenylene, butylene, For example, ethyl benzene a or ethyl phenyl methyl I α, such as ethyl benzene halides (please read the notes on the back before filling out this page), ethyl benzene chloride or ortho, as in example 0 ethyl; benzene) Ethylphenethylphenethyl bromide printed in tri-, tetra-, or pentachlorochlorostyrene, bromostyrene or fluorostyrene; and alpha or dot-halostyrene ( For example, α-chlorostyrene, α-bromostyrene, chlorochloroethyl ethyl or / 9-bromostyrene). The transparent polystyrene resin may further include other monomers which can be copolymerized with the styrene monomer, such as acrylonitrile, methyl methylpropionate, and maleic anhydride. The manufacturing method of the transparent polystyrene resin is not particularly limited. The weight average molecular weight of the transparent polystyrene resin is preferably 200,000 to 350,000. Component (B) The polystyrene fine particles useful in the present invention preferably have a refractive index close to that of the polystyrene resin as the matrix. The average particle size is usually 1 to 10 wm, preferably 3 to 10 wm, and more preferably 3 to 6 / um. If it is less than .1 wm, too fine particles will re-aggregate, resulting in Insufficient dispersion, it often develops fish eyes and deteriorates the appearance of the sheet. If it exceeds 10 / m, coarse particles may impair the appearance and cause the sheet to crack during stretching. Cross-linked styrene This paper is sized according to Chinese National Standard (CNS) A4 (210X297 mm) -7-83.3.10,000 Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs A7 B7 V. Description of invention (5) Average of fine particles The particle size is a 50% volume average particle diameter as measured using a Cou 11 er counter. In the first specific example of the present invention, the amount of the crosslinked polystyrene fine particles is 0.01 to 1% by weight, preferably 0.02 to 0.1% by weight based on the amount of the resin composition. In the second specific example of the present invention, the amount of the particles is 0.01 to 0.1% by weight, preferably 0.01 to 0.06% by weight based on the amount of the resin composition. If the amount of cross-linked polystyrene fine particles is lower than the lower limit of each of the above specific examples, the number of protrusions formed on the surface during stretching is too small to produce improved stretched sheets and special stacked sheets that form articles Anti-blocking. If it exceeds the respective upper limits defined above, the particles are likely to re-aggregate, reducing the transparency and appearance of the sheet * and causing the sheet to break during stretching. Generally, the cross-linked polystyrene fine particles can be obtained as a copolymer of a compound having a vinyl group and a cross-linking agent having at least two vinyl groups in one molecule, both of which can be subjected to radical polymerization. Examples of the former include monovinyl compounds such as styrene and (meth) acrylates, which can be used alone or in combination with K. Examples of the crosslinking agent include divinylbenzene, ethylene glycol di (meth) acrylate, and trimethylolpropane triacrylate. The method for producing particles includes a method that can provide the polymer in the form of particles, such as suspension polymerization, dispersion polymerization, emulsion polymerization, and a method that includes grinding the polymer obtained by solution polymerization or bulk polymerization. Preparation Example Preparation of Crosslinked Polystyrene Fine Particles

1,860 g of water, 2 18 g of a 10% by weight aqueous solution of polyvinyl alcohol, 1, 3 50 S styrene, 20.4 s divinylbenzene, and 13.5 g of perylene laurel oxide A large paper size of the base installer applies the Chinese National Standard (CNS) A4 specification (210X297 mm) -8 _ ~~ 83. 3. 10,000 (Please read the notes on the back before filling this page) A7 B7 printed by the Consumer Cooperatives of the Ministry of Standards of the People's Republic of China 5. Description of the invention (6) In a bucket, stir with a high-speed mixer for 10 minutes at 5,000 rp π to obtain a monomer formulation containing finely divided droplets. Put 1, 120 g of water and 123 g of a 10% by weight aqueous solution of polyvinyl alcohol in a 5 liter four-necked flask, replace with K nitrogen inside, and raise the temperature to 70 ° C °. The monomer formulation was added over 2 hours. After the addition was completed, the mixture was allowed to stand at 80 ° C for 4 hours, and M was polymerized and heated. The resulting suspension was cooled to room temperature and allowed to stand for 2 days. After removing the supernatant, the remaining contents were dried in a hot air dryer at 50 ° C. The dry powder and powder were ground in a coffee mill, and then classified using an air classifier (a mini classifier made by NP K Company) to obtain polymer beads having an average particle size of 4.3 w in. Ingredient (C) The rubber-modified polystyrene resin used in the present invention can be prepared by conventional methods such as bulk polymerization and suspension polymerization, so that the obtained resin contains a diene rubber component having an average particle size of 0.1 to 3 mm. The content of the diene rubber component in the rubber-modified polystyrene resin is usually 1 to 15% by weight. Examples of the diene rubber component include a diene polymer containing at least one conjugated 1,3-diene such as butadiene, isoprene, 2-gas-1,3-butadiene, 1-chloro -1, 3 _ Ding Erxian and Liu Liao B are steeper. The diene rubber component contained in the rubber-modified polystyrene resin has an average particle size of 0.1 to 0.3 wm, preferably 0.5 to 2.5 w in c if the particle size is less than 0. At 1 wm, the size of the rubber protrusions formed on the surface of the stretched sheet will be less than the surface, especially when the sheet is stacked and punched. This paper size applies the Chinese National Standard (CNS) A4 specification (210X297). Mm) 9-83. 3.10,000 (please read the notes on the back before filling out this page) Pack _ Order A7 B7 Printed by the Consumers' Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 5. Description of the invention (7) 1 1 Its blocking resistance 0 Large particles with an average diameter of more than 3 uim will cause the surface to be roughened and the transparency reduced. 0 The diene rubber component in the resin composition, the degree of curvature 1 | 0. 006--0. 06% by weight 9 is preferably 0.01 -V_- 0.04% by weight C If the rubber is first read, the concentration of the ingredients is lower than 0.6% by weight when the silicone oil is uniform. Apply the reading back I Sr I on the surface of the sheet. If the amount of cross-linked polystyrene fine particles is added M to compensate for the rubber I I 1 I When the concentration of the rubber component is short > The aggregate of the added particles will roughen the sheet Material matters 1 I Surface 〇 If the rubber concentration exceeds 0.06, the transparency will be reduced when the weight is weighted, and C will be filled again .. Write the above-mentioned rubber ingredients used in the modified polystyrene resin for ordering page 1 The term "average particle size" means the average sub-size (D), obtained from the sample. 1 1 Quotient of a sample resin according to the following formula in the ultra-thin cross-section of the transparent resin mold phase of the resin was measured by 1,000 Γ rubber polymer particles.圚 TTf f ± (with a diameter of the same area as the protruding particle phase 1) 1 I Σ η ΐ di 4 1 1 1 D = ~ 1! Σ η ΐ D i 3 where ni represents a large number of rubber polymers having a 圚 equivalent 'diameter di 0 1 When necessary η Κχ m The resin composition of the present invention may further include additives 1 1 I »such as lubricants, plastics Chemical agent and coloring agent 0 I 1 The resin composition to be formed into a sheet and stretched is dry-blended with transparent polystyrene tree 1 1 grease and cross-linked polyethylene thin φ 丄 m in Henger (H e η SC ne 1) Mixer double 1 type mixer, etc. or mix the main particles of resin composition containing a large amount of m fine particles with transparent poly +-f * this vinyl resin to make 0 1 1 I resin composition The material is usually stretched at a temperature of 110-35 ° ct, preferably 120-125 ° c. 1 The stretching ratio in each direction (length direction and transverse direction) is usually 2 1 1 This paper size applies Chinese national standards (CNS) A4 specification (210X297 mm) _! 〇_ 83.3. 〖0,000 Ministry of Economic Affairs Printed by the Consumer Standards Cooperative of the Central Bureau of Standards A7 B7 V. Description of Invention (8) ~ 5. The better stretching in all directions is 2.5. The thickness of the stretched sheet obtained in accordance with the present invention is usually from 0.1 to 0.1 mm. The heart of the stretched polystyrene resin sheet according to the present invention can be evenly coated with silicone oil. Its main ingredient contains dimethylsiloxy and has an Ostwald viscosity of 100 at 20 ° C. ~ 200,000 cSt, or coated with an emulsion prepared by emulsifiers alone or in combination with additives such as anti-fog agents or antistatic agents. The appropriate spreading amount of the silicone oil is preferably about 10 to 150 rag / in2, and the dryness can be felt at the spreading amount. The present invention is described in detail with reference to the examples, but it should be noted that the present invention is not limited thereto. EXAMPLES In the examples, the average particle size was measured as a 50% average particle size using a Coulter (C II II t e r ·) counter. The properties of the prepared stretched sheet were evaluated and rated as follows. 1. Release property (anti-blocking property) A two-wheel stretched polystyrene resin sheet was formed into a container on a thermoforming machine (FK-0431-01, manufactured by Asano Selsakusyo) (open tip diameter: 90 mm; closed) Bottom diameter: 60 in in; height: 50 mm). Twenty containers thus formed were stacked and cut with a die cutter under pressure. The measurement load is 2 ks of the stacked height (h) and the removed load height (h 〇), and the recovery rate U is obtained according to the following formula M: (h 〇)-(h) recovery rate U) --- x 1 00 (h) This paper size applies Chinese National Standard (CNS) A4 specifications < 210 X 297 mm) -1 1-83. 3.10,000 (Please read the precautions on the back before filling this page) • Installation · Order A7 B7 V. Description of the invention (9) The release property of the molded product is rated as A to D according to the recovery rate under M. A ... not less than 30% B not less than 20¾ and less than 30¾ C ..... not less than 10: ¾ and less than 20% D ..... less than 1 0% 2. Transparency The turbidity of a 180 wm-thick sheet was measured using a turbidimeter manufactured by Suga Test Instruments. Transparency is rated as A to D according to turbidity under K. A ... not higher than 1¾ B ..... higher than 1% and not higher than 1.5% C ..... higher than 1.5 ~ 2. 0% D .... .Higher than 2.0¾ 3. The number of protrusions on the surface is measured with a two-dimensional surface roughness meter "Surfc 〇m" manufactured by Tokyo Precision Co., Ltd. The protrusions have a height of 0.2 ~ lwra and a length of 20cm sample sheet. Number 0 A ... 1 5 1 or printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back before filling this page) Β ..... 10 1- 150 C ..... 51 to 100 D ..... 50 or 4 under .Polysilicone oil logo Place 10 sheets of A 4 size on each other and place a 10 kg load on it. 1 2 hours. Divide the A 4 H material area into 100 segments | Measure the proportion of the area with a map-like pattern with the naked eye. This paper size applies the Chinese National Standard (CNS) A4 specification (210X297 public directors) _, 〇_ 83. 3. 10,000 printed by the Consumer Cooperatives of the Central Standardization Bureau of the Ministry of Economic Affairs A7 _B7_ V. Description of the invention (ίο) A ... ... not higher than 5 1¾ B ..... higher than 5% and not higher than 25% C ..... higher than 251 and not higher than 50¾

D ..... Above 50 I 5. Coke + ib. The ratio of fish eyes including staining and contamination due to resin coking is measured with the naked eye using a 50 X magnifying glass and 0.2 mm m or more. A ... not higher than 5¾ B ..... higher than 5% and not higher than 25% C ..... higher than 25% and not higher than 50¾ D ..... high The transparent polystyrene resin and cross-linked polystyrene fine particles (S Β X -8, (Prepared by Sekisui Plastic Co., Ltd.) mixed, and the obtained resin composition was extruded into a sheet by an extruder at a temperature of 1 2 5 ° C and a draw ratio of 2.5, and the sheet was biaxially stretched in all directions, M to obtain a 180 mm thick biaxially stretched sheet. The surface of the stretched sheet was coated with silicone oil at a spread of 40 in g / m2. The properties of the sheet are shown in Table 1. Comparative Examples 1 to 3 Biaxially prepared in the same manner as in Example 1 except that a resin composition obtained by changing the rubber component concentration and the average particle size of the rubber component contained in the rubber-modified polystyrene shown in Table 1 was used. Stretched polystyrene grease sheet. The characteristics of the obtained sheet are shown in Table 1. As shown in Table 1, none of the obtained sheets satisfies all necessary characteristics. This paper size is applicable to China National Standard (CNS) A4 (210X297 mm) — ι3 _ 83.3.10,000 --Ί ------ -----Please read the precautions on the back before filling this page ) The prescribed statement issued five M SI ss IS Ή ί 2 ε S Μ ro

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VV (Please read the precautions on the back before filling out this page). Loading., Τ Defective Nqli ^ -ffl ralliN ^ e in the printed container of the Ministry of Economic Affairs, Central Standards Bureau.谌 (% + J *) _ 弋 writes the chain 鹚 蝼 蹈 (la rr) Zb-Ns1sgf 蝤 S chain destroys 2 leaching M «Acid 蝤 U-PM) 5- < 曷 0¾),", ¥ 屮 铤 © 阵 天 r < l Gingival knowledge: Tibetan Mastiff paper size, using China National Standard (CNS) A4 (210X297 mm) 14 83. 3. 10,000 Pro 225 A7 B7 V. Description of the invention (12) Trade Examples 5 to 8 A transparent polystyrene resin having different average particle sizes shown in Table 2 and a rubber modified polystyrene resin having a rubber content of 6 wt% (MC 6 5 6 0, (Chevr ο η Chemical Co., Ltd.) mixed, 俾 may have the rubber concentration attributed to the rubber modified polystyrene resin, as shown in Table 2. The mixture was then cross-linked with polystyrene having an average particle size shown in Table 2. Ethylene fine particles (Technopolymer, manufactured by Sekisui Plastic Co., Ltd., or Microgel, manufactured by Nippon Paint Co., Ltd.) were mixed. The obtained resin group salt was extruded by an extruder. A sheet was made, and at a temperature of 125¾ and a stretch ratio of 2.5, M was biaxially stretched in all directions, and M was obtained as a biaxially stretched sheet of 180 w in thickness. The surface of the stretched sheet The coating was coated with a silicone oil with a spreading amount of 40 mg / m 2. The properties of the sheet were not as good as those in Table 2. Comparative Examples 4 to 7 Except changing the rubber concentration of the rubber modified polystyrene polystyrene shown in Table 2 And the average particle size and the amount of crosslinked polystyrene fine particles and the average particle size M, biaxially stretched polystyrene resin concrete was prepared in the same manner as in Example 5. The properties of the obtained sheet are shown in the table. 2. ——Ί ——--- 1 ----- /.i ... (Please read the notes on the back before filling in this page) Order- ^ line _ Printed by the Staff Consumer Cooperative of the Central Bureau of Standards, Ministry of Iron Economy The size of the cracked paper is applicable to the Chinese National Standard (CNS) Α4 specification (210X297 mm) _ ί r L 83. 3. 10,000 5

A B7 13 7 (\ 明 说明 发 [-繇 繇 繇 9! I # 繇 qq SM®qq Η 岛 繇 繇 cofl # M »iM ΜΜ tof # Compliance 0 0 C-J0.0Γ0 S0.0S.0 α 3 3 S0,0C-JoΓ0S.0 εοοinch00 ο, I 2Ln.coWOJinch.! — I00 αCSJ0.009 S0.0 S.0 § · 0 (Please read the precautions on the back before filling this page)

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VV 0000 90 10.0 Printed by the Consumers' Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs nJl * N 隹 嘁 Interpretation of Sl / N 53 脒: 1 il +->-. I_Y soap (say 3 乇 ¥ 屮 ® No array (% -p3_Y ^ w 甶 chain il® (3 days, "K 屮 sJJT'izk-Nalgam S Award * 2" and «« Acid 镟 二 镟 君 嗞 嗞 This paper size applies to China National Standard (CNS) A4 size (210X297) (Centi) 16 83. 3.10,000 A7 B7 V. Description of the invention (Η) If it has been fully explained and confirmed, since the surface of the polystyrene stretched sheet of the present invention has fine unevenness uniformly on the surface, polysiloxane The oil can be evenly applied thereto, and the sheet exhibits improved blocking resistance while maintaining its transparency, and can prevent appearance deterioration and cracking due to heat deterioration of rubber and foreign substances. Therefore, even if When the shaped articles obtained from the sheets are stacked, they are also easy to separate without sticking lotus. Although the present invention has been described in detail with reference to specific embodiments thereof, anyone skilled in the art will understand that the spirit of the present invention is not departed from Outside the scope, you can make various changes and improvements. -J -------- 装-.1-/ {(Please read first Note on the back, please fill out this page again)-Ordered by the Central Standards Bureau of the Ministry of Economic Affairs, printed by the Shellfish Consumer Cooperative, this paper is in Chinese National Standards (CNS) A4 size (210X297 mm) 17 83. 3.10,000

Claims (1)

7? S7S2S5 C8 .-Β8- 88. 9.-1 Amendment printed by the Consumers' Cooperative of Intellectual Property Bureau of the Ministry of Economic Affairs 6. Application for patent scope 丨 1. A biaxially stretched polystyrene resin sheet Obtained by axially stretching a resin composition containing: (A) a transparent polystyrene resin having a weight average molecular weight of 200,000 to 350,000, and (B) crosslinked polystyrene fine particles * which is 0.01 to 1% by weight of the resin composition and an average particle size of 1 to 10 wm. 2. If the biaxially stretched polystyrene resin sheet of item 1 of the patent application range, wherein the average particle size of the cross-linked polystyrene fine particles is 3 ~ 10wra. 3. The biaxially stretched polystyrene resin sheet according to item 1 of the patent application, wherein the amount of the crosslinked polystyrene fine particles based on the resin composition is 0.02 to 0.1% by weight. 4. A biaxially stretched polystyrene resin sheet obtained by biaxially stretching a resin composition * The resin composition contains (A) a transparent polystyrene resin having a weight average of 200,000 to 350,000 Molecular weight, (B) cross-linked polystyrene fine particles, which are 0.006 to 0.06% by weight of the resin composition and have an average particle size of 1 to 10 «and (C) a rubber-modified polystyrene resin, which has an average A diene rubber component having a particle size of 0.1 to 0.1, in which the diene rubber component concentration of the rubber-modified polystyrene resin is 0.01 to 0.1% by weight of the resin composition. 5. For example, the biaxially stretched polystyrene resin base material of item 4 of the patent application, wherein the average particle size of the cross-linked polystyrene fine particles is 3 ~ 10wm. 6. Biaxially stretched polystyrene resin sheet as in item 4 of the scope of patent application * wherein the amount of cross-linked polystyrene pellets is 0.01 to 0.06% by weight of the resin composition. This paper size applies to China National Standard (CNS) A4 specification (210 X 297 mm) ^ -Packing ------ I -------- (Please read the note 2 on the back before filling this page ) T7? S7S2S5 C8 .-Β8- 88. 9.-1 Amendment printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 6. Application scope of patents 1. A biaxially stretched polystyrene resin sheet, which is borrowed Obtained by biaxially stretching a resin composition comprising: (A) a transparent polystyrene resin having a weight average molecular weight of 200,000 to 350,000, and (B) crosslinked polystyrene fine particles * which It is 0.01 to 1% by weight of the resin composition and the average particle size is 1 to 10 wm. 2. If the biaxially stretched polystyrene resin sheet of item 1 of the patent application range, wherein the average particle size of the cross-linked polystyrene fine particles is 3 ~ 10wra. 3. The biaxially stretched polystyrene resin sheet according to item 1 of the patent application, wherein the amount of the crosslinked polystyrene fine particles based on the resin composition is 0.02 to 0.1% by weight. 4. A biaxially stretched polystyrene resin sheet obtained by biaxially stretching a resin composition * The resin composition contains (A) a transparent polystyrene resin having a weight average of 200,000 to 350,000 Molecular weight, (B) cross-linked polystyrene fine particles, which are 0.006 to 0.06% by weight of the resin composition and have an average particle size of 1 to 10 «and (C) a rubber-modified polystyrene resin, which has an average A diene rubber component having a particle size of 0.1 to 0.1, in which the diene rubber component concentration of the rubber-modified polystyrene resin is 0.01 to 0.1% by weight of the resin composition. 5. For example, the biaxially stretched polystyrene resin base material of item 4 of the patent application, wherein the average particle size of the cross-linked polystyrene fine particles is 3 ~ 10wm. 6. Biaxially stretched polystyrene resin sheet as in item 4 of the scope of patent application * wherein the amount of cross-linked polystyrene pellets is 0.01 to 0.06% by weight of the resin composition. This paper size applies to China National Standard (CNS) A4 specification (210 X 297 mm) ^ -Packing ------ I -------- (Please read the note 2 on the back before filling this page )