JPH05295216A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide the thermoplastic resin composition maintaining the properties of an acrylic resin such as weather resistance, surface hardness and transparency and further having properties such as flexibility, processability and low temperature characteristics. CONSTITUTION:The thermoplastic resin composition is produced by blending an acrylic resin with a hydrogenated product of a terpolymer composed of a block comprising an aromatic vinyl monomer and a block comprising isoprene and/or butadiene and having a number-average molecular weight of 30000-70000.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent thermoplastic resin composition which is highly flexible, has excellent processability and weather resistance.

[0002]

BACKGROUND OF THE INVENTION Olefinic resins and olefinic elastomers are used alone as molding compositions because of their flexibility and extrusion processability, or as compositions containing other thermoplastic elastomers and softening agents. Has been used. For example, it is a molding material for automobile bumpers and console panel surfaces, but since it has no polar groups, it is inferior in paintability, printability, and color development during coloring, and the fact that it is not possible to select the type of color during processing is the reality. Is. Further, there is a problem that the surface hardness is low in contrast to the flexibility, and the scratch resistance is poor. However, due to the recent increasing interest in environmental issues, recyclable materials have come to the forefront, and researches for improvement of olefin-based polymers have been intensively studied.

On the other hand, acrylic resins used as molding materials are used in various materials by taking advantage of their characteristics such as transparency, color developability, weather resistance and surface hardness. In particular, it is often used outdoors as a weather-resistant resin having good color developability, and is also used for window glass applications, transparent materials such as fluorescent lamp covers, and the like. In addition, since it decomposes into a monomer when heated, it is also being studied as a recyclable material. However, acrylic resins generally have poor flexibility and low impact strength,
Much work has been done to improve flexibility.

ABS resin, which can satisfy the physical properties of both of these resins to some extent, is
There are impact resistant acrylic resins and the like, but both are known to have poor weather resistance because the rubber component for imparting impact resistance has a chemically unstable double bond in the main chain. There is. In order to satisfy the weather resistance, AES resin, acrylic resin in which acrylic acid ester rubber is dispersed, and the like have been studied, but their use is limited due to the balance between physical properties and cost.

On the other hand, vinyl chloride-based polymers are inexpensive and widely used along with olefin-based polymers, and their hardness and mechanical properties can be controlled by the amount of plasticizer, so that they actually have high hardness. , Low hardness from the field that competes with acrylic resin that requires transparency,
It has been used for many materials in the field of polyolefin where flexibility is required, and it has been advantageous due to its low cost. However, the vinyl chloride polymer originally has poor processability and requires a large amount of plasticizer. The plasticizer has a problem of a phenomenon of precipitating on the surface due to aging (predout). Further, this polymer is decomposed by heating to produce a halogen-containing product, and therefore, it is practically difficult to recycle it, and therefore its replacement is required.

Therefore, if an acrylic resin and an olefin polymer can be compounded, surface properties such as surface hardness of the acrylic resin, weather resistance, and color developability can be maintained, and the flexibility and processing of the olefin polymer can be further maintained. sex,
It should be possible to provide properties such as low temperature properties and to obtain a material that is recyclable.

However, the conventional styrene-saturated thermoplastic elastomer and the acrylic resin have low miscibility, and when the composition is manufactured for such purpose, delamination, devitrification, and reduction in mechanical strength should be avoided. Cannot be produced, and a good molded product has not been produced yet.

[0008]

SUMMARY OF THE INVENTION The object of the present invention, however, is to maintain the surface properties such as surface hardness of an acrylic resin such as surface hardness, weather resistance, transparency and the like, while maintaining flexibility and low temperature properties. It is to provide a novel thermoplastic resin composition provided with.

[0009]

As a result of investigations by the present inventors, the above-mentioned problems have been solved by a block composed of an aromatic vinyl monomer having a specific molecular structure and molecular weight as a thermoplastic elastomer with respect to an acrylic resin. And a saturated thermoplastic elastomer composed of isoprene alone or a block composed of both isoprene and butadiene in a specific proportion.

That is, according to the present invention, (A) an acrylic resin and (B) an a-b-a structure (wherein a is a block composed of an aromatic vinyl monomer, and b is an isoprene-butadiene copolymer). A terpolymer having a partially or completely hydrogenated block of the polymer), wherein (i) the number average molecular weight of each a block is 3000
˜15000, (ii) the content of the a block in the block copolymer is 15 to 35% by weight, (iii) the weight ratio of isoprene and butadiene constituting the b block is 40/60 or more and 100/0 or less, ( iv) A hydrogenated product of a thermoplastic block copolymer having a number average molecular weight of 30,000 to 70,000 and a molecular weight distribution by gel permeation chromatography of 1.20 or less (A) / (B ) = 10/90 to 90/10 in a weight ratio of the thermoplastic resin composition is provided.

The present invention will be described in detail below.

In the present invention, the acrylic resin used as the component (A) is a single polymer of methyl methacrylate or a small amount of another copolymerizable monomer containing methyl methacrylate as a main component. It is a copolymer, and the manufacturing method is not particularly limited. Examples of the copolymerizable component that can be used include acrylic acid, metal salts of acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, s-butyl acrylate, t-butyl acrylate, and acrylic such as 2-ethylhexyl acrylate. Acid esters, methacrylic acid, methacrylic acid metal salts, ethyl methacrylate, n-butyl methacrylate, s-butyl methacrylate, t-butyl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, cyclohexyl methacrylate, etc. Methacrylic acid esters, acetic acid esters such as vinyl acetate, styrene, aromatic vinyl compounds such as α-methylstyrene, maleic anhydride, maleic acid mono- and dialkyl esters, and maleimides such as N-phenylmaleimide. And these are 1 May be used or in any combination, and in any ratio. It is necessary that the copolymerization ratio with methyl methacrylate does not significantly change the properties of the acrylic resin, and specifically, it can be used at about 0.01 to 30% by weight.

The saturated thermoplastic elastomer used as the component (B) is a block a composed of an aromatic vinyl monomer and a partially or completely hydrogenated block of an isoprene-butadiene copolymer. The block b has a weight ratio in the range of 40/60 to 100/0.

The aromatic vinyl monomer used here is
Examples thereof include styrene and α-methylstyrene, and these can be used alone or in combination of two or more kinds. The block a made of an aromatic vinyl monomer needs to have a number average molecular weight in the range of 3,000 to 15,000, and the block a is in the range of 15 to 35% by weight based on the total weight of the block b. Need to be in. Further, it is important that the block a is uniformly included in the change in the molecular weight of (B), that is, it has a clearly ternary block structure, and the molecular weights of both blocks a are equal. Only when these requirements are satisfied, miscibility with the component (A) is obtained, and good mechanical strength, transparency, etc. are obtained as the desired thermoplastic resin composition.

In block b, isoprene and butadiene are both contained in the isoprene / butadiene weight ratio of 40 /
60-100 / 0, more preferably 50 / 50-100
It can be used in a ratio of / 0, and the primary structure of the molecular chain can be used either randomly or in a block structure depending on the purpose. Since isoprene has a higher molecular mobility than butadiene because it has a methyl group branching compared to butadiene, those with a high ratio of isoprene are more flexible, and those with a high ratio of butadiene as a harder elastomer. Due to the properties, it is possible to determine the properties of the elastomer by any choice. However, when it deviates from this range, the desired good miscibility in the composition with the component (A),
Mechanical strength cannot be obtained. Further, the unsaturated double bond is hydrogenated in order to improve the heat resistance and weather resistance of this block segment, but since the glass transition temperature hardly changes, the thermoplastic property can be maintained. The hydrogenation rate is 70 in order to satisfy the desired heat resistance and weather resistance.
% Or more is preferable. By satisfying all of these requirements in each of the block a and the block b, the miscibility of the saturated thermoplastic elastomer as the component (B) with the acrylic resin as the component (A) is improved for the first time, and a good machine is obtained. Strength is obtained.

Further, the thermoplastic elastomer composed of the block a and the block b satisfying the above-mentioned requirements is required to have a number average molecular weight in the range of 30,000 to 70,000. The block structure of (B) is a-
By having a ternary block structure of b-a, the domain formed by the block a serves as a pseudo-crosslinking point and can exert mechanical strength as a composition. By satisfying all of these requirements, the thermoplasticity of the saturated thermoplastic elastomer as the component (B) is exerted,
The miscibility with the component (A) is improved, and good mechanical strength and moldability are obtained as a composition composed of the component (A) and the component (B). When these requirements to be satisfied deviate from the ranges described above, the desired miscibility with the acrylic resin as the component (A) cannot be obtained, and the mechanical strength of the composition decreases.

As described above, all the requirements for constituting the component (B) are necessary to obtain the desired thermoplastic composition, and if any of the requirements is not satisfied, the desired goodness is obtained. It is impossible to achieve the objectives such as high miscibility, mechanical strength, moldability, and transparency.

The saturated thermoplastic elastomer satisfying the above requirements has a melt flow rate of 230 ° C. and 2.1.
A load of 6 to 100 g / 10 min under a load of 6 kg is preferably used, and a load of 5 to 80 g / 10 min is more preferable.

The method for synthesizing the saturated thermoplastic elastomer can be obtained by obtaining a polymer by anionic living polymerization using an organic alkali metal catalyst which is usually performed, and then hydrogenating the polymer. For example, using an anionic polymerization initiator such as n-butyllithium or s-butyllithium, a saturated aliphatic hydrocarbon compound such as hexane, heptane, or cyclohexane, or an aromatic hydrocarbon compound such as benzene, toluene, or xylene is used as a solvent. A living polymer is produced by anionically polymerizing an aromatic vinyl monomer under a temperature condition of 30 to 60 ° C., and then a conjugated diene monomer such as isoprene or butadiene is dropped into the system. Block copolymerization is performed, and then an aromatic vinyl monomer is dropped again into the system to produce a ternary block copolymer. In addition, under the same conditions as above, an aromatic vinyl monomer and then a conjugated diene monomer such as isoprene and butadiene are dropped into the system to produce a living polymer of a binary block copolymer. , This one
2-dibromoethane, 1,4-dibromobutane, 1,4
The ternary block polymer can also be obtained by coupling with a dihalogen compound such as dichlorobenzene or a tin compound such as tin tetrachloride. Alternatively, when a bifunctional anionic polymerization initiator such as 1,4-dilithiobutane or dilithionaphthalene is used as a polymerization initiator, a conjugated diene monomer and then an aromatic vinyl monomer are sequentially added to form a ternary compound. A block copolymer is produced. When carrying out the polymerization, dimethyl ether as a cocatalyst,
Ethers such as diethyl ether, tetrahydrofuran and dioxane, glycol ethers such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether, triethylamine, N, N, N ′,
When a Lewis base such as amines such as N′-tetramethylethylenediamine and N-methylmorpholine is used in a range of about 0.1 to 1000 times the number of moles of the metal cation of the polymerization catalyst, isoprene and / or The microstructure of the block segment consisting of butadiene is changed to contain vinyl bonds. This vinyl structural unit is 4
When it is 0% or more, it has a glass transition temperature in the vicinity of room temperature, and vibration damping performance in the vicinity of room temperature can be imparted (JP-A-2-102212). Then, when the ternary block copolymer reaches a desired molecular weight, active hydrogen compounds such as alcohols, carboxylic acids and water are added to terminate the polymerization.

Next, the saturated thermoplastic elastomer is produced by hydrogenating the obtained copolymer. As the hydrogenation catalyst, a homogeneous catalyst or a heterogeneous catalyst can be used. When using a homogeneous catalyst, a combination of an organic transition metal catalyst (eg, nickel acetylacetonate, cobalt acetylacetonate, nickel naphthenate, cobalt naphthenate, etc.) and a metal alkylated product of aluminum, an alkali metal, an alkaline earth metal, etc. The Ziegler catalyst, etc., is used in an amount of about 0.01 to 0.1 mol% per double bond of the polymer to be hydrogenated. The hydrogenation reaction is carried out at room temperature to 150 ° C. and normal pressure to 50 kg / cm ² of hydrogen pressure,
It takes about 1 to 50 hours. After completion of the reaction, acidic water is added to the vessel and vigorously stirred to dissolve the hydrogenation catalyst in water. The desired saturated thermoplastic elastomer is obtained by removing the aqueous phase of the two phases that have been phase-separated and further distilling off the solvent.

When a heterogeneous catalyst is used, nickel, cobalt, palladium, rhodium, ruthenium, platinum, etc. may be used alone or in combination with silica, diatomaceous earth, alumina,
It is used by supporting it on activated carbon or the like, and its amount is suitably 0.5 to 10% by weight based on the weight of the polymer. This is added to the polymerization reaction liquid. At this time, ethers such as diethyl ether, tetrahydrofuran and dioxane, and alcohols such as ethanol and isopropanol can also be used as a mixed solvent. The hydrogenation reaction is from room temperature to 250 ° C,
It is carried out under a hydrogen pressure of atmospheric pressure to 200 kg / cm ² , and about 1 to 50
Finish in time. After completion of the reaction, the reaction product is taken out from the container, the catalyst is filtered off, and the solvent is distilled off from the obtained filtrate to obtain the desired saturated thermoplastic elastomer.

Component (A) 10 thus obtained
90% by weight and 90 to 10% by weight of the component (B) are mixed by a physical mixing method to obtain a thermoplastic resin composition which is rich in desired flexibility, is excellent in processability and weather resistance, and has a transparent feeling. Obtainable. Further, when higher weather resistance is required for the composition, a combination of (A) component / (B) component in a weight ratio range of 25/75 to 90/10 is more preferable.

The thermoplastic resin composition of the present invention comprises a reinforcing agent,
Various additives such as fillers and pigments can be optionally contained. For example, reinforcing agents such as carbon black, mica, glass fiber, carbon fiber, fillers such as alumina, talc, zeolite, ferrite, calcium carbonate, aluminum hydroxide, dyes, pigments, flame retardants, ultraviolet rays. Organic or inorganic additives used as absorbents and other functional additives. The addition amount thereof is in the range of the amount generally used, and for example, 0.001 to 50 parts by weight, or in some cases, a larger amount can be used based on 100 parts by weight of the total resin composition. Further, the thermoplastic resin composition of the present invention may contain, if desired, polyolefins such as polyethylene and polypropylene, olefinic plasticizers such as polybutene, polyisobutylene, and process oil within a range that does not impair the physical properties.

The method of mixing the respective components constituting the composition can be carried out by a conventional and conventional method, and the method is not particularly limited. For example, it can be carried out by a method of mixing in a molten state with a usual melt kneader such as an extruder or a kneader. At this time, the components (A) and (B) may be melt-kneaded at the same time, or the remaining components may be added to the melt-kneaded product of one of them by arbitrary selection and melt-kneaded. Good, it is necessary to knead the resin at a temperature not lower than the temperature at which each raw material resin melts and flows, and more specifically, at a temperature within a range that does not cause deterioration.
However, it is more preferably performed at 180 to 280 ° C.

[0025]

EXAMPLES Next, the present invention will be specifically described with reference to examples. In addition, the part in each Example represents a weight part. Moreover, each physical property was calculated | required by the method shown below. (1) Tensile physical property test: Measured using a dumbbell No. 2 test piece in accordance with JISK-7113. (2) Hardness: ASTMD-2240 or JISK-
It measured based on 6301. (3) Oil resistance test: 120 in JIS No. 2 oil at room temperature
It was immersed for a period of time and the change in appearance was evaluated. (4) Pencil scratch resistance: The scratch resistance was evaluated by a method and an apparatus based on JISK-5400. (5) Delamination: The injection molded test piece was bent and evaluated visually. (6) Dispersion state: A test piece cooled in liquid nitrogen was fractured, the fractured surface was observed with a scanning electron microscope, and the dispersed particle size was measured and evaluated.

The saturated thermoplastic elastomer used in the present invention was manufactured as follows.

Production of Saturated Thermoplastic Elastomer (1) 500 parts of cyclohexane and 12 parts of s-butyllithium were charged in a pressure resistant reaction vessel equipped with a stirrer and a dropping funnel, heated to 50 ° C., and styrene 60 was fed from the dropping funnel. Parts continuously, then 280 parts isoprene continuously, and then 60 parts styrene continuously.
Polymerization was carried out for a time. Thereafter, the reaction system was replaced with hydrogen, 20 parts of a diatomaceous earth-supported nickel catalyst was added, and the mixture was reacted at 150 ° C. for 7 hours under a hydrogen pressure of 15 kg / cm ² . The reaction product was diluted with cyclohexane, the catalyst was filtered off, and the filtrate was concentrated and dried under reduced pressure to obtain a saturated thermoplastic elastomer (1).
Got It was confirmed by NMR that the copolymer was a styrene-hydrogenated isoprene-styrene ternary block copolymer, and the styrene content was 30.8%. From the GPC analysis, the number average molecular weight of the styrene block was 5,400, the number average molecular weight of the isoprene block was 24,300, and the number average molecular weight of the whole was 35,100. The hydrogenation rate according to the iodine value was 93.2%, and the hydrogenation rate for the benzene ring by NMR was 0.7%. Melt flow rate is 230
It was 75.4 g / 10 minutes at 2.degree. C. and a load of 2.16 kg.

Production of Saturated Thermoplastic Elastomer (2) 500 parts of cyclohexane and 9 parts of s-butyllithium were charged into a pressure resistant reactor equipped with a stirrer and a dropping funnel,
The temperature was raised to 50 ° C., 60 parts of styrene was continuously charged from a dropping funnel, 280 parts of isoprene was continuously charged, and then 60 parts of styrene was continuously charged to carry out polymerization for 10 hours. Thereafter, the reaction system was replaced with hydrogen, 30 parts of a diatomaceous earth-supported nickel catalyst was added, and the mixture was reacted at 150 ° C. for 10 hours under a hydrogen pressure of 15 kg / cm ² . The reaction product was diluted with cyclohexane, the catalyst was filtered off, and the filtrate was concentrated and dried under reduced pressure to obtain a saturated thermoplastic elastomer (2).
Got It was confirmed by NMR that the copolymer was a styrene-hydrogenated isoprene-styrene ternary block copolymer, and the styrene content was 31.5%. From the GPC analysis, the number average molecular weight of the styrene block was 10,300,
The number average molecular weight of the isoprene block was 44,500, and the total number average molecular weight was 65,100. The hydrogenation rate according to the iodine value was 98.0%, and the hydrogenation rate of the benzene ring according to NMR was 0.8%. Melt flow rate is 23
It was 6.5 g / 10 minutes at 0 ° C. and a load of 2.16 kg.

Production of Saturated Thermoplastic Elastomer (3) 500 parts of cyclohexane and 4.5 parts of s-butyllithium were charged into a pressure-resistant reaction vessel equipped with a stirrer and a dropping funnel, the temperature was raised to 50 ° C., and the mixture was added from the dropping funnel. 20 parts of styrene were continuously charged, then 273 parts of isoprene were continuously charged, and then 20 parts of styrene were continuously charged to obtain 8 parts.
Polymerization was carried out for a time. Then, the reaction system was replaced with hydrogen, 20 parts of a diatomaceous earth-supported nickel catalyst was added, and the mixture was reacted at 150 ° C. for 10 hours under a hydrogen pressure of 15 kg / cm ² . The reaction product was diluted with cyclohexane, the catalyst was filtered off, and then the filtrate was concentrated and dried under reduced pressure to obtain a saturated thermoplastic elastomer (3). It was confirmed by NMR to be a styrene-hydrogenated isoprene-styrene ternary block copolymer, and the styrene content was 12.8%. Also GPC
The number average molecular weight of the styrene block was 7.9.
00, the number average molecular weight of the isoprene block is 107,6
00, the total number average molecular weight was 123,400.
The hydrogenation rate according to the iodine value was 95.6%, and the hydrogenation rate for the benzene ring by NMR was 1.2%. The melt flow rate was 0.18 g / 10 minutes at 230 ° C. and a load of 2.16 kg.

Production of Saturated Thermoplastic Elastomer (4) A pressure resistant reaction vessel equipped with a stirrer and a dropping funnel was charged with 75 parts of butadiene, 500 parts of cyclohexane and 4.5 parts of s-butyllithium and heated to 50 ° C. 25 parts of styrene was continuously charged from the dropping funnel, then 7 parts of butadiene
5 parts were continuously charged, then 25 parts of styrene was continuously charged, and polymerization was carried out for 8 hours. After that, the reaction system was replaced with hydrogen, 20 parts of a diatomaceous earth-supported nickel catalyst was added, and the mixture was reacted at 150 ° C. for 13 hours under a hydrogen pressure of 15 kg / cm ² . The reaction product is diluted with hot xylene and the catalyst is filtered off,
Then, the filtrate was concentrated and dried under reduced pressure to obtain a saturated thermoplastic elastomer (4). It was confirmed by NMR to be a quaternary block copolymer of hydrogenated butadiene-styrene-hydrogenated butadiene-styrene, and the styrene content was 24.8%.
Met. From the GPC analysis, the number average molecular weight of the styrene block was 7,700, the number average molecular weight of the butadiene block was 51,000, and the number average molecular weight of the whole was 11
It was 7,400. Hydrogenation rate based on iodine value is 93.1
%, The hydrogenation rate of the benzene ring by NMR was 1.7%. The melt flow rate was 0.55 g / 10 minutes at 230 ° C. and a load of 2.16 kg.

[0031]

[Table 1] [Examples 1 to 3 and Comparative Examples 1 and 2] An acrylic resin and a thermoplastic block copolymer were mixed with a mixer in a composition shown in Table 2 and placed in a twin screw extruder at 200 ° C and 200 rpm in a nitrogen atmosphere. Supply and melt mixed. Table 3 shows the physical properties measured by molding the obtained mixture into various test pieces with an injection molding machine.

[0032]

[Table 2]

[0033]

According to the present invention, by mixing an acrylic resin with a saturated thermoplastic elastomer having a specific structure and physical properties, it is transparent and excellent in processability and weather resistance. Provided is a thermoplastic resin composition having a feeling.

Claims (2)

[Claims] 1. (A): an acrylic resin; and (B): an aba structure (wherein a is a block composed of an aromatic vinyl monomer, and b is an isoprene-butadiene copolymer). (I) the number average molecular weight of each a block is 3000 to 1 in the terpolymer having a partially or completely hydrogenated block).
5000, (ii) the content of a block in the block copolymer is 15
˜35 wt%, (iii) the weight ratio of isoprene and butadiene constituting the b block is 40/60 or more and 100/0 or less, (iv) the number average molecular weight of the block copolymer is 30,000 to
A hydrogenated product of a thermoplastic block copolymer having a molecular weight distribution of 70,000 and a molecular weight distribution by gel permeation chromatography of 1.20 or less is (A) / (B) = 10.
The thermoplastic resin composition contained in a weight ratio of / 90 to 90/10. 2. The melt flow rate of the hydrogenated product of the thermoplastic block copolymer as the component (B) at 230 ° C. under a load of 2.16 kg is 5 to 100 g / 10 minutes.
The thermoplastic resin composition described.