JPS62164745A - Transparent heat-resistant thermoplastic resin composition having excellent impact resistance - Google Patents

Abstract

PURPOSE:To obtain the titled compsn. which has excellent transparency, excellent appearances of moldings and improved impact strength, by blending a styrene copolymer resin with a methyl methacrylate resin and a graft copolymer resin is such a proportion as to give a specified refractive index. CONSTITUTION:A resin compsn. contains 85-10wt% styrene copolymer resin (A) having a light transmittance of 80% or above, obtd. by copolymerizing 20-40wt% methacrylic acid with 75-45wt% styrene and 5-25wt% methyl methacrylate, 5-80wt% methyl methacrylate copolymer resin (B) having a light transmittance of 80% or above and 10-40t% graft copolymer (C) having a light transmittance of 60% or above, obtd. by copolymerizing 80-20wt% mixture contg. 10-90wt% methyl methacrylate in the presence of 20-80wt% rubbery polymer, in such a proportion that a difference in refractive index between a mixture of the components A and B and the component C is wittrin + or -0.002.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a new and useful thermoplastic resin composition, and more particularly, the present invention relates to a new and useful thermoplastic resin composition. The present invention relates to a resin composition containing a copolymer resin, which can be mainly applied to molding processes, has a high heat distortion temperature, and has excellent properties such as impact strength, transparency, and appearance of molded products.

[Prior art and problems to be solved by the invention] Conventionally, polystyrene resins, styrene-acrylonitrile copolymer resins (As resins), and methyl methacrylate resins have been known as resins with excellent transparency. In addition to transparency, these resins have excellent dimensional stability, electrical properties, and colorability, and are therefore used in a wide variety of fields. The reality is that their use in fields that require such performance, such as medical instruments, light electrical parts, and automobile parts, is limited because they are not necessarily satisfactory in terms of strength.

Therefore, in order to improve the heat distortion temperature, which is a drawback of polystyrene resin, conventional methods have been taken to copolymerize styrene and methacrylic acid, but the styrene-methacrylic acid copolymer resin obtained in this way When using a styrene-based copolymer resin, the thermal deformation temperature in question can be significantly improved, but it cannot be denied that the application is limited due to its inferior impact strength.By the way, such a styrene-based copolymer resin As a method to improve the impact strength of
A method of mechanically mixing a thermoplastic elastomer such as a block copolymer resin is known, but when a styrene-butadiene block copolymer resin is mixed with a styrene copolymer resin in this way, the impact strength is Although this is improved, it cannot be denied that there is a drawback that transparency is significantly reduced.

On the other hand, while improving the heat distortion temperature and impact strength of As resins and methyl methacrylate resins, / IJ car is a mechanically mixed engineered plastic such as nate resin, which improves heat distortion temperature and impact strength. Although the strength is improved, the difference in refractive index significantly reduces transparency, resulting in a so-called pearlescent luster as disclosed in JP-A No. 49-353. This is not preferable because it will also significantly limit the

[Means for solving problems]

However, in view of the various drawbacks of the prior art as described above, the present inventors have improved the heat distortion temperature and impact strength, which are the drawbacks of polystyrene resin, and have also improved the heat distortion temperature and impact strength of polystyrene resin. In view of the existence of problems such as a significant decrease in transparency caused by improving the heat distortion temperature and impact strength, etc., we have carried out intensive studies with the aim of solving these problems. When a methyl methacrylate resin is blended with a specific styrene copolymer resin, a composition with a high heat distortion temperature can be obtained without sacrificing transparency, and a composition made by blending both resins. They have also discovered the surprising property that the composition is homogeneous, and that a linear relationship is established between the refractive index of the composition and the weight ratio of both resins.

However, even if the composition is composed of such a specific styrene copolymer resin and methyl methacrylate resin, the impact strength is insufficient. A specific graft copolymer resin is blended with the specific graft copolymer resin, and the refractive index (n28; hereinafter the same) of the mixture of the specific styrene copolymer resin and methyl methacrylate resin is the specific graft copolymer resin described above. The present inventors have demonstrated that by using a resin composition having a refractive index within a certain range, the heat distortion temperature, impact strength, and appearance of the molded product can be improved without significantly sacrificing transparency. had already been discovered at that time (Japanese Patent Application No. 60-217506).

By the way, in such three-component resin compositions,
Although it has excellent bending impact strength such as Izotsu impact strength, it is inferior to impact strength due to falling objects such as falling weight impact strength and falling ball impact strength, so we have conducted extensive studies with the aim of solving these problems. A specific styrene copolymer resin obtained by copolymerizing styrene, methacrylic acid, and methyl methacrylate, a methyl methacrylate resin, and a specific graft copolymer resin are combined with these styrene copolymer resins and methyl methacrylate resin. On the other hand, the refractive index of the mixture consisting of the former two components with the resin is 1.5.
±0 of the refractive index of a specific graft copolymer resin that meets two conditions: a refractive index within the range of 15 to 1.545, and a light transmittance compliant with JISK-6717 of 60 or more.
．． It has been discovered that using a resin composition blended within the range of 002 provides excellent transparency, impact strength, and appearance of molded products, and further improves impact strength. The present invention was completed by discovering that the present invention can also be applied to specific fields such as automobiles, as mentioned above.

That is, in the present invention, as essential components, 20 to 40% by weight of methacrylic acid, 75 to 45% by weight of styrene, and 5 to 25% by weight of methyl methacrylate, a total amount of 100% by weight.
The refractive index is 1, which is obtained by copolymerizing it so that it becomes a heavy polymer.
．． 85 to 10% by weight of a styrenic copolymer resin (A) having a light transmittance of 548 or higher and a light transmittance of 80 or higher according to JISK-6717 (the same applies hereinafter), and a light transmittance of 8.
5 of the methyl methacrylate resin (B) which is 01 or more
~80% by weight of a mixture consisting of 10-90% by weight of methyl methacrylate and 90-10% by weight of styrene in the presence of 20-80% by weight of a comb polymer.
or copolymerize 5-40% by weight of methyl methacrylate, 90-1% by weight of styrene, and 5-50% by weight of acrylonitrile in the presence of 20-80% by weight of the rubbery polymer. 80~ of a mixture consisting of ts
20% by weight, the refractive index is 1.5.
15 to 1.545 and 10 to 40% by weight of the graft copolymer resin C) having a light transmittance of 601 or more, and the total amount of these three essential components (A), (B) and C) is 100% by weight. The refractive index of the mixture of the resin component and the resin component (0) in a specific ratio that is proportional to each other by weight is within the range of ±0.002 of the refractive index of the (Q resin component). The object of the present invention is to provide a thermoplastic resin composition.

As described above, the resin composition of the present invention contains the above-mentioned essential main components of styrene copolymer resin (A), methyl methacrylate resin (B), and graft copolymer resin (Q). (
A) resin component and (8) resin component, (A) resin component and (C) resin component, or (8) resin component and (C)
A two-component system with a resin component can never achieve the intended purpose.

That is, first, a two-component system of (A) and (B) has insufficient impact strength, second, a two-component system of (A) and (Q) significantly reduces transparency, and furthermore, a two-component system of (A) and (Q) has insufficient impact strength. A two-component system of (Q) and (Q) is not preferred because the heat distortion temperature is significantly lowered.

In other words, by using the thermoplastic resin composition of the present invention, excellent properties such as heat deformation temperature, impact strength, and appearance of molded products can be exhibited without significantly sacrificing transparency.

Here, the above-mentioned styrene-based copolymer resin (2) refers to 20 to 40% by weight of methacrylic acid and 75 to 4% by weight of styrene.
5% by weight and 5 to 25% by weight of methyl methacrylate (assuming, of course, that the total amount of each monomer is 100% by weight) in the presence of a chain transfer agent and a radical generator, A material having a refractive index of 1.548 or more and a light transmittance of 80% or more, which is obtained by copolymerization by a known and commonly used polymerization method such as solution polymerization, emulsion polymerization, or suspension polymerization, is used.

An example of the method for preparing the styrene copolymer resin (A) is as follows: 20 to 40 t4, preferably 25 t4 of methacrylic acid.
-35% by weight, 75-45% by weight of styrene, preferably 70-50% by weight, and 5-35% by weight of methyl methacrylate.
A mixture consisting of 25% by weight, preferably 10 to 20% by weight (of course, the total amount of each of these monomers is 100% by weight), and a known and commonly used chain transfer agent and radical generator. suspension stabilizers such as polyvinyl alcohol, sodium polyacrylate, potassium polyacrylate, polyvinylpyrrolidone, methylcellulose, hydroxymethylcellulose,
Furthermore, in water in which a suspension aid such as sodium chloride, sodium phosphate, or sodium alkylsulfonate is dissolved,
After completion of the polymerization reaction, dehydration, washing, and drying can be performed before use, and if necessary, antioxidants, plasticizers, or Adding lubricants etc.
Thereafter, it can also be provided in the form of granulation using an extruder or the like.

In the copolymer resin (A), as essential components,
20-40 weight ratio of methacrylic acid and 75-4 of styrene
The product obtained by copolymerizing 5 to 25 weight units of methyl methacrylate with 5 to 25 weight units of methacrylic acid is used, but if this methacrylic acid is less than 20 weight units, as a result,
A composition obtained by blending the resin component (A) with both resin components 03) and (C) is not preferable because the heat distortion temperature decreases.
If it is less than 5% by weight, the resin component (A) itself is not preferable because silver streaks or flashes will occur on the surface of the molded product during injection molding, significantly impairing the appearance of the molded product. As a result, (A) and (
B) and the prisoner and C), or (A) and (B) and C
) is undesirable because silver streaks and flashes occur in either case.

Next, the typical methyl methacrylate resin (B) mentioned above includes a homopolymer of methyl methacrylate, methyl methacrylate of 80 parts by weight or more and less than 100 parts by weight, and methyl methacrylate of less than 20 parts by weight. Various acrylic esters such as acrylate, ethyl acrylate or n-butyl acrylate; Various methacrylic esters other than methyl methacrylate such as ethyl methacrylate, n-butyl methacrylate or cyclohexyl methacrylate; or "acrylic acid, There are copolymers of methyl methacrylate and various monomers that can be copolymerized, such as methacrylic acid, styrene, or acrylonitrile, but among these, those with a light transmittance of 804 or more are preferred, and methyl methacrylate is preferable. It is suitable to use a homopolymer of

An example of the method for preparing the methyl methacrylate resin (B) is as follows: 1 g of methyl methacrylate alone or together with methyl methacrylate! Alternatively, there is a method in which two or more of the various monomers listed above are subjected to bulk polymerization, bath liquid polymerization, or suspension polymerization in the presence of a chain transfer agent and a radical generator. Of course, general commercially available products that can be used for this purpose can be used as they are.

Furthermore, the above-mentioned graft copolymer resin C) is a mixture consisting of 10 to 90 parts by weight of methyl methacrylate and 90 to 10 parts by weight of styrene in the presence of 20 to 80 parts by weight of a rubbery polymer. Alternatively, in the presence of 20 to 80 parts by weight of a copolymer, 5 to 49 parts by weight of methyl methacrylate, 90 to 1 parts by weight of styrene, and 5 parts by weight of acrylonitrile are copolymerized. ~50 weight range, obtained by combining 80 to 200 to 20 weight of a mixture, the refractive index is within the range of 1.515 to 1.545, and the light transmittance is 60 modulus or more. finger body

The general graft straw of the graft copolymer resin (C) thus obtained, that is, the ratio of the weight of the core portion to the weight of the trunk portion, is suitably within the range of 0.2 to 1.2.

What about the rubbery polymer mentioned here? A homopolymer of butadiene, such as lipadiene rubber or styrene-butadiene copolymer rubber, or a copolymer of a vinyl monomer copolymerizable with sitadiene, etc., can be used.

First, one of the conditions for the graft copolymer resin (C) is that its light transmittance should be 60 coefficients or more, but one with a light transmittance of less than 60 coefficients is used. In this case, as a result, the resin composition obtained from the resin components (5) and (B) described above and the resin component (C) will have significantly poor transparency, which is not preferable.

Next, the resin component (6) has a refractive index of 1.
One of the conditions is that the refractive index of the resin component (C) be within the range of 515 to 1.545. The refractive index of the mixture of barrel (A) resin component and @) resin component is within a certain range of the refractive index of the (C) resin component, that is, within a range of ±0.002 of the refractive index of the C) component. This is absolutely necessary in order to do so.

In addition, in preparing the graft copolymer resin (C'), known and commonly used polymerization methods such as emulsion polymerization, emulsion/suspension polymerization, solution polymerization, or bulk polymerization can be applied as is.
Of course, general commercially available products used for blending this type of vinyl chloride resin can be used as they are.

Therefore, the thermoplastic resin composition of the present invention contains, as essential components, 85 to 10% by weight of a styrene copolymer resin (A), 5 to 80% by weight of a methyl methacrylate resin (B), and a graft. 10 to 40% by weight of the copolymer resin (C) so that the total amount of these three essential components is 100% by weight, and the first two of these three essential components, that is, styrene. The refractive index of the blend of the copolymer resin (A) and the methyl methacrylate resin @) is within the range of the remaining component, that is, the refractive index is 1.515 to 1.545, and the light transmittance is 604 or more. It is an essential condition that the refractive index of the graft copolymer resin (C) has a specific condition of being within the range of ±0.002. For (C), if the blending amount is less than 10% by weight, the impact strength will decrease, which is undesirable.On the other hand, if it exceeds 40% by weight, the heat deformation temperature will increase significantly. This is not preferable because it results in a decrease in K.

Furthermore, when using a blend of styrene copolymer resin (A) and methyl methacrylate resin (B) whose refractive index exceeds the refractive index of the graft copolymer resin (C) by 100002. This is not preferable because the transparency will be significantly deteriorated.

In order to prepare the desired thermoplastic resin composition using the three essential components listed above, known and commonly used blending methods are used, for example, using a roll or a Banbury mixer.
Alternatively, a blending method by heating and melting using an extruder may be applied as is.

The thermoplastic resin composition of the present invention may further contain various known and commonly used additive components such as a heat stabilizer, an antioxidant, an ultraviolet absorber, a plasticizer, a coloring agent, a lubricant, or an antistatic agent, as necessary. Of course, the three essential components (A), (B), and (C) described above can be blended as appropriate during the blending process.

[Use of invention]

The thus obtained transparent heat-resistant thermoplastic resin composition of the present invention with excellent impact resistance has excellent heat distortion temperature, impact strength, and transparency, as well as excellent appearance of molded products, so it is suitable for use. 9.VTR tape cassettes, audio tape cassettes, food processors, iron water tanks, lighting covers, circle tube connectors, and other home appliance related parts such as printer covers, floppy disk cases, copy machine sorters, etc. OA related parts; Automotive related parts such as light guide plates, instrument panels, and Langhau songs; Optical related parts such as cameras and optical prisms; Medical related parts such as dialyzers and animal breeding cages; Food containers such as microwave tableware, etc. It covers a wide range of fields.

〔Example〕

Next, the present invention will be explained in more detail with reference examples, examples, and comparative examples. In the following, all parts and parts are based on weight unless otherwise specified. The physical properties of the molded articles obtained in the Examples and Comparative Examples were evaluated in the following manner.

■ Heat deformation temperature Compliant with ASTM D-648 (264psi)K.

■ Impact strength Method A ASTM D-256 Izot impact strength test method (1/
4 inches, with chi].

■ Impact strength Method B Using an impact deformation tester compliant with JIS K-5400, a plate-shaped test piece with a length of 50 m and a width of 50 m and a thickness of 3 mm was measured with a radius of 3. A /4-inch firing mold and a receiver are sandwiched between the stand and a "weight" with a mass of 0.5 kg is dropped onto the firing mold from an arbitrary height to determine the 501 failure height of the test piece. It is expressed as the product of the 50% failure height and the mass.

■Light transmittance Compliant with JIS K-6717.

■ Appearance of molded product Using an in-line screw injection molding machine where the cylinder temperature is 270℃, the mold temperature is 60℃, and the length is 50+A.
By injection molding a plate-shaped molded product with a width of 50m and a thickness of 3+m, the appearance of the resulting molded product was visually observed for the presence of silver streaks and flash. Cases in which streaks or flashes were observed were marked with an "xj" mark, and cases in which none of them were observed were marked with an "○" mark.

Reference Example 1 [Preparation method of styrenic copolymer resin (A)] In a 51 stainless steel reactor equipped with a turbine-type stirring blade, 2
000.9 distilled water and added each IOF Cal? as a suspension stabilizer. oxymethylcellulose and 0
．． 05.9 and sodium dodecylbenzenesulfonate, and then 550.9 of styrene and 15
0g methacrylic acid, 150. Methyl methacrylate of F, di-t@rt-butyl peroxyhexahydroterephthalate of 2I, tert-butyl perbenzoate of 11 and α-methylstyrene dimer of 8II were added sequentially, then at 400 rpm. The temperature was raised while stirring, and from the time when 90'CK was reached, 15011 methacrylic acid was added at a constant rate over 6 hours, and after the addition was completed, the same temperature was maintained for 3 hours, and then the temperature was raised to 120°C. This temperature was further maintained for 3 hours to complete the polymerization.

Next, the granular copolymer resin thus obtained is washed,
After dehydration and drying, a desired resin having a refractive index of 1.556 and a light transmittance of 88 was obtained.

Hereinafter, this will be abbreviated as resin (A-1).

Reference Example 2 (same as above) Polymerization was carried out in the same manner as in Reference Example 1, except that the amount of styrene used was changed to 'Y500.9 and the amount of methyl methacrylate used was changed to 2009, and the refractive index was 1.
A target resin having a light transmittance of 553 and a light transmittance of 88 was obtained. Hereinafter, this will be abbreviated as resin (A-2).

Reference example 3 (same as above) The amount of styrene used is 650I! , the initial amount of methacrylic acid charged was 125 g, and the amount of methacrylic acid added at constant speed was 125 g.
51, and the amount of methyl methacrylate used is 100g.
Polymerization was carried out in the same manner as in Reference Example 1, except that the resin had a refractive index of 1.565 and a light transmittance of 884. Hereinafter, this will be abbreviated as resin (A-3).

Reference Example 4 [Preparation method of graft copolymer resin (C)] 1.900. ! i
2010 gin sodium aqueous solution 501 as an emulsifier was also added and dissolved.
Further, 1.0451 ml of polybutadiene latex with a solid content of 57.4 ml was added.

Next, 84 g of methyl methacrylate and 361 styrene were charged together with o, s, p tert-dodecyl mercaptan and 4I tris(nonylphenyl) phosphite, and the temperature was started to rise to 65°C while blowing nitrogen gas. At that point, add 100 g of distilled water containing 2 g of potassium persulfate and continue to raise the temperature to 7
From the time the temperature reached 0°C, 196I methyl methacrylate and 84 g of styrene were added at a constant rate over 2.5 hours, and after the addition was completed, the same temperature was maintained for 1.5 hours, and then the temperature was raised to 80°C. The mixture was then kept at the same temperature for an additional 1 hour to carry out emulsion polymerization.

Afterwards, it is coagulated with magnesium sulfate, washed,
The desired resin was dehydrated and dried to obtain the desired resin in the form of Meso powder. Hereinafter, this will be abbreviated as resin (C-1), and the refractive index of this material was 1,523, and the light transmittance was 75°. Reference Example 5 (same as above) yf! I) Instead of butanoene rubber latex, 1,4632 styrene-butadiene copolymer rubber latex with a solid content of 41 and a styrene content of 1,4632 was used, and the composition of the initial monomers was changed. , 54.
F's methyl methacrylate and 54 g of styrene; 12.
Emulsion polymerization was carried out in the same manner as in Reference Example 4, except that the acrylonitrile winter (9) and the acrylonitrile (IJ Luki) were changed. A resin was obtained. below,
This is abbreviated as resin (C-2).

Reference Example 6 Resin (A-1) obtained in Reference Example 1 and light transmittance of 9
2nd name “Sumipex-BMFfJ (Custom Chemical Industry)
Methyl methacrylate resin manufactured by Co., Ltd.; hereinafter, this will be abbreviated as resin CB-2). ] in various composition ratios and kneaded and extruded using an extruder with a diameter of 50 mm and a cylinder temperature of 240°C.Then, the refractive index of each blend thus obtained was determined by Abb* ) When measured with a refractometer (the same applies hereinafter), the refractive index of each compound and these resins (A-1) and resin (B-1) are as shown in the following formula.
It was confirmed that a linear relationship was established between the blended weight ratios of both resins.

That is, weight of resin (B-1) (7) weight of resin (A-1) (7) weight of resin (B-1) (
(g) is X, and the refractive index of the blend consisting of these two resins is nl, n, = -0-063x, + 1,556 CI
) holds true.

Reference Example 7 Resin (A-2) and resin (B-1) obtained in Reference Example 2 were blended at various composition ratios, and the same procedure as Reference Example 6 was carried out without kneading and extrusion, and then the refractive index was measured. As shown in the following formula, the refractive index of each compound and these resins (A-2
) and the blended weight ratio of both resins (B-1) were confirmed to have a similar linear relationship.

That is, the weight of resin (A-2) a (g) + the weight of resin (B-1) (
jI) as x2, and the refractive index of the blend consisting of both of these resins as n2, n2=-0,060x2+1.553 (1
A relationship of 13 is established.

Reference Example 8 Reference Example 6 except that the resin (A-3) obtained in Reference Example 3 and the resin (B-1) were blended at various composition ratios.
When the same procedure was carried out as shown in the following equation, it was confirmed that a linear relationship similarly holds between the refractive index of each compound and the blended weight ratio of both resins.

That is, weight of resin (B-1) C) weight of resin (A-3) (2) weight of resin (B-1) G
) is I, and the refractive index of the blend consisting of both these resins is n3, then n −−0,072xs + 1.565
[1111) A relationship of one holds true.

Example 1 ±0.0 of the refractive index of the resin (C-1) obtained in Reference Example 4
Resin (A-1) and resin (B-1) are blended at a composition ratio as shown in Table 1 so as to fall within the range of 02, that is, within the range of 1.521 to 1.525, Furthermore, this resin (c-i) is also blended to increase the cylinder temperature to 240.
The mixture was kneaded and extruded using an extruder having a diameter of 50 mφ at a temperature of 50° C. to obtain pellets.

Next, this pellet was dried at 105° C. for 3 hours, and then molded using an in-line screen injection molding machine to obtain test pieces for various physical property tests.

The physical properties of the test pieces thus obtained and evaluated are summarized in the same table.

Examples 2 to 4 Resin (A-1) and resin (B-1) obtained in Reference Example 1
) and the resin (C-2) obtained in Reference Example 5, or a resin having a refractive index of 1.521 and a light transmittance of 60 or more [Kane Ace B-56J C manufactured by Kanebuchi Chemical Industry Co., Ltd. Graft copolymer resin; hereinafter, this will be abbreviated as resin (C-3). ], or has a refractive index of 1.539 and a light transmittance of 60 or more [Kane Ace B-22J (
Graft copolymer resin manufactured by the above company; hereinafter, this will be referred to as resin (C
-4). ) and one type of resin (C) respectively, and resin (C-2), (C-3) and (C-
The resin (A-1
) and resin (B-1), and further resin (C-2)
, (C-3) or (C-4) were also blended, and thereafter kneaded and extruded in the same manner as in Example 1, dried to prepare each test piece, and then the physical properties were evaluated. , the results shown in the same table were obtained.

Examples 5 and 6 Resin (A-2) and resin (B-1) obtained in Reference Example 2
) and resin (C-3) or resin (C-4), respectively, within a range of ±0.002 based on the refractive index of resin (C-3) or (C-4). Resin (A-2) and resin (B-1) at the composition ratio shown in Table 1.
and further blended with resin (C-3) or (C-4), kneaded and extruded in the same manner as in Example 1, dried to prepare each test piece, and then measured the physical properties. When we conducted the evaluation, we obtained the results shown in the same table.

Example 7 The composition ratio as shown in Table @1 was adjusted so that the refractive index of the Gra7t copolymer resin (C-3) fell within the range of ±0.002, that is, within the range of 1.519 to 1.523. Resin (A-
3) and resin CB-1), and further this resin (C
-3) was also blended, and then kneaded and extruded in the same manner as in Example 1, dried to prepare each test piece, and then evaluated the physical properties.The results are shown in the table. was gotten.

Comparative Example 1 Into the same reactor as in Reference Example 1, 2,000 # of distilled water was charged, and hlo and 9 were added as suspension stabilizers, respectively.
of Cal dissolves oxymethyl cellulose and 0.059 of sodium dodecylbenzenesulfonate, and then adds 700. ! Styrene (i'), methacrylic acid (1501), t-butyl peroxyhexahydroterephthalate (2II), tart-butyl perbenzoate (II) and 8 g of α-methylstyrene dimer were sequentially charged, Thereafter, the refractive index was set to 1 in the same manner as in Reference Example 1.
．． A control styrenic copolymer resin having a light transmittance of 3>69 and a light transmittance of 86 was obtained. Hereinafter, this resin (A'
-1).

Hereafter, the refractive index of resin (C-3) is ±0.0.
Resin (A'-1) and resin (B-1) were blended in a composition ratio as shown in Table 1 so that the composition fell within the range of 0.02,
Furthermore, resin (C-3) was also blended and a control test piece was prepared in the same manner as in Example 1 without kneading and extrusion, and then dried.Then, the physical properties were evaluated, and as shown in the table. The results were obtained.

Comparative Example 2 Except that the composition of the initial charge monoparticle used was changed to 350# styrene, 1509 methacrylic acid, and 35011 methyl methacrylate, and the amount of α-methylstyrene dimer used was changed to 6NK. A control styrenic copolymer resin having a refractive index of 1.535 was obtained in the same manner as in Reference Example 1. Hereinafter, this will be abbreviated as resin (A'-2).

Hereafter, this resin (A'-1) will be replaced with resin (A'-1).
2) was used, but kneading and extrusion were carried out in the same manner as in Comparative Example 1, followed by drying to prepare a control test piece. Then, the physical properties were evaluated, as shown in Table 1. The results were obtained.

Comparative Example 3 The composition of the initially charged monomers used was 2101 styrene and 150. A control styrene with a refractive index of 1.521 was prepared in the same manner as in Reference Example 1, except that F was changed to methacrylic acid and 490 g of methyl methacrylate, and the amount of α-methylstyrene dimer was changed to 61. A copolymer resin was obtained. Hereinafter, this will be abbreviated as resin (A'-3).

From now on, resin (A'-3) is used instead of resin (A'-1).
Test pieces were prepared in the same manner as in Comparative Example 1, except for changing the use of .

Comparative Examples 4 to 6 Resin (A-1) and resin (A-1) were prepared in such a manner that any one of the three resin components, ie, @) or C) was missing, and the composition ratios were as shown in Table 1, respectively. Resin (B-1) [Comparative Example 4], or resin (A-1) and resin (C-
3) [Comparative Example 5], or resin (B-1)
and resin (C-3) [Comparative Example 6], and then dried to prepare each test piece in the same manner as in Example 1 without kneading and extrusion, and then the physical properties were evaluated. They are summarized in Table 1.

Comparative Example 7 As an example of a case in which both the resin components ω) and (C) are omitted and only the residual resin component is used, the resin (A-1) obtained in Reference Example 1 was heated at a cylinder temperature of 240°C. The pellets were obtained by kneading and extrusion using an extruder with a diameter of 50@IIφ, and then drying at 105°C for 3 hours. Test pieces were prepared and their physical properties were evaluated, and the results shown in Table 1 were obtained.

Comparative Example 8 As an example of a case where only a resin component is used (without any use of both resin components Q), resin (B-1) is used instead of resin (A-1). A control test piece was prepared in the same manner as in Comparative Example 7, except that the test piece was changed to, and the physical properties were then evaluated. Table 1 summarizes the results.

Comparative Example 9 The mixing weight part ratio of the resin (A-1) obtained in Reference Example 1 and [Asaflex 810J [: styrene-butadiene block copolymer resin manufactured by Asahi Kasei Corporation] was 50:
The compound No. 50 was kneaded and extruded using an extruder with a diameter of 50 mφ and a cylinder temperature of 240°C (to make it red), and was dried at 105°C for 3 hours, and then an in-line screw with a cylinder temperature of 240°C was used. A control test piece was prepared by molding with an injection molding machine, and then the physical properties were evaluated, and the results shown in Table 1 were obtained.

Comparative Example 10 Resin (B-1) and Tubarex 7025AJ [polycargenate resin manufactured by Mitsubishi Chemical Industries, Ltd.] were blended in a mixing weight part ratio of 50:50.

The pellets were pelletized using an extruder set at a cylinder temperature of 270°C, and then dried at 110°C for 4 hours, and the resulting pellets were molded using an in-line screw injection molding machine to form control test pieces. When the material was prepared and its physical properties were evaluated, the results shown in Table 1 were obtained.

Comparative Example 11 A control sample was prepared in the same manner as Comparative Example 10, except that "Tyryl 783" [styrene-acrylonitrile copolymer resin manufactured by Asahi Kasei Industries, Ltd.] was used instead of resin (B-1). A test piece was prepared and then its physical properties were evaluated, and the results shown in Table 1 were obtained.

Comparative Example 12 "Tyril 783" was dried at 90°C for 3 hours, and then molded into 250
A control test piece was prepared by molding at a cylinder temperature of 0.degree. C., and then the physical properties were evaluated, and the results shown in Table 1 were obtained.

Comparative Example 13 "Dick Styrene
A control test piece was prepared by molding at 0°C.
Next, the physical properties were evaluated, and the results shown in Table 1 were obtained.

〔Effect of the invention〕

As is clear from the results in Table 1, the transparent heat-resistant thermoplastic resin composition with excellent impact resistance according to the present invention is superior to polystyrene resin, methyl methacrylate resin, and styrene-acrylonitrile copolymer resin. It is known that it has a significantly high heat distortion temperature and impact strength.

In addition, the thermoplastic resin composition of the present invention not only has much better transparency and impact strength than conventional blended products, but also has much higher transparency and impact strength than conventional blended products. It is known that, like copolymer resins, it also has a high degree of transparency with a light transmittance of 801 or higher.

As described above, the thermoplastic resin composition of the present invention has excellent properties such as heat distortion temperature, impact strength, and transparency, as well as appearance of molded products, and therefore has a wide range of applications, and therefore has a wide range of uses. It can be used to prepare various molded products such as

Claims (1)

[Claims] 1. (A) 20 to 40% by weight of methacrylic acid, 75 to 45% by weight of styrene, and 5 to 25% by weight of methyl methacrylate.
The refractive index (n^2^8_D) obtained by copolymerizing the total amount of 100% by weight is 1.54.
85-1 of a styrenic copolymer resin having a light transmittance of 80% or more according to JIS K-6717.
0% by weight, and (B) light transmittance in accordance with JIS K-6717 is 8.
10-90% by weight of methyl methacrylate and 90-10% by weight of styrene in the presence of 5-80% by weight of a methyl methacrylate resin of 0% or more and 20-80% by weight of (C) a rubbery polymer. 80-20% by weight of a mixture consisting of
or 5-49% by weight of methyl methacrylate, 90-1% by weight of styrene and 5-50% by weight of acrylonitrile in the presence of 20-80% by weight of the rubbery polymer.
The refractive index (n^2^8_D) is 1.515 to 1.5 obtained by copolymerizing 80 to 20% by weight of a mixture consisting of
45 and has a light transmittance of 60% or more according to JIS K-6717.
0 to 40% by weight as essential components, and the total amount is 100% by weight.
% by weight, and the refractive index (n^2^8_D) of the mixture of the resin component (A) and the resin component (B) in the above-mentioned specific ratio is the same as that of the resin component (C). A transparent heat-resistant thermoplastic resin composition having particularly excellent impact resistance, characterized in that the refractive index (n^2^8_D) is within the range of ±0.002. 2. The composition according to claim 1, wherein the rubbery polymer is a butadiene homopolymer. 3. The composition according to claim 1, wherein the rubbery polymer is a copolymer of butadiene and styrene.