JPH0420943B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a polymer composition having improved properties, and more specifically, the present invention relates to a polymer composition having improved properties.More specifically, the present invention relates to a polymer composition having improved properties. It has excellent heat resistance and solvent resistance, and is made by mixing a copolymer obtained by graft polymerizing acrylic acid ester.
The present invention relates to a resin composition that has a high degree of impact strength and is suitable for various industrial materials. [Prior art and its problems] Thermoplastic polyesters have been consumed in large quantities as fibers and films since ancient times, but polyalkylene terephthalate has particularly excellent technical properties such as rigidity, hardness, abrasion resistance, and mechanics. In recent years, it has been used as a molding material in a wide range of fields, including electrical and electronic equipment parts and automobile parts, due to its thermal and thermal stress capabilities and rapid processability. However, polyalkylene terephthalate as an engineering plastic has
There is a drawback that the impact strength is insufficient when a notch is attached, and by improving this, it can be expected to be used in a wider range of applications, so there have been many attempts to improve this drawback. has been done. That is, an attempt was made to improve the impact strength of polyalkylene terephthalate by mixing a modified elastomer, etc. For example, an attempt was made to mix polybutylene terephthalate with a normal ABS resin consisting of conjugated diolefin, styrene, and acrylonitrile (Japanese Patent Publication No. 1973- 30421), etc. are known. By the way, normal ABS resin is vinyl chloride resin,
Although it greatly improves the impact strength of vinyl polymers such as polystyrene, it is not very effective as an impact modifier for non-vinyl polymers, and in fact
As seen in Publication No. 30421, the impact strength of polybutylene terephthalate has hardly been improved. Addition of a modified elastomer has been proposed as a means to improve the impact strength of polyalkylene terephthalate, but although the impact strength is improved, other useful properties are significantly deteriorated, and the effect of the improvement is Often halved. [Means for Solving the Problems] An object of the present invention is to impart excellent impact resistance to thermoplastic polyesters represented by polyalkylene terephthalate without reducing other useful properties. That is, as a result of extensive studies, the present inventors selected a graft copolymer having specific components and composition, and by defining the blending ratio of this graft copolymer and polyalkylene terephthalate within a range, Extremely good impact resistance, heat resistance,
An impact-resistant resin composition having solvent resistance is obtained,
It has been found that the object of the invention is achieved. The present invention consists of acrylonitrile, aromatic vinyl, and acrylic ester with respect to 40 to 95% by weight of a rubbery backbone polymer mainly composed of conjugated diolefin, and the weight ratio of these is acrylonitrile: aromatic vinyl: acrylic ester = 5. ~
50:20-60:monomer mixture 60-5
5 to 50 parts by weight of graft copolymer obtained by grafting 95 to 50 parts by weight of thermoplastic polyester resin
The object of the present invention is to provide an impact-resistant resin composition prepared by mixing parts by weight. The most important feature of the resin composition of the present invention is that the notched isot impact strength corresponding to the notch sensitivity is extremely high even when the proportion of the graft copolymer in the composition is low. In other words, even when the proportion of the graft copolymer is low, the impact strength, especially up to -40°C, is significantly improved, and as the proportion of the graft copolymer increases, the impact strength of the composition improves dramatically. There is a particular thing. This is an extremely important feature from the purpose of the present invention, which is to impart excellent impact resistance while maintaining other properties of polyalkylene terephthalate. Surprisingly, the resin composition of the present invention not only has excellent impact resistance but also excellent heat resistance, that is, the composition has a high heat distortion temperature. Normally, when a rubber-like polymer with a high rubber content is mixed with polyalkylene terephthalate such as polybutylene terephthalate, the heat distortion temperature is considered to be significantly lowered, but in the composition of the present invention, the graft copolymer In addition to acrylonitrile and aromatic vinyl, it contains a specific acrylic acid ester as an essential graft monomer in consideration of copolymerization reactivity with both of them, so that the heat distortion temperature can be lowered even in mixtures with a high graft copolymer content. is high. The resin composition of the present invention is also characterized by excellent solvent resistance. In other words, even after being immersed in a solvent for a long period of time, there is very little decrease in impact strength.
Moreover, the original high impact strength can be maintained. Thermoplastic polyester resins suitable for the purposes of the invention are those containing aromatic dicarboxylic acids or their reactive derivatives, such as dimethyl esters or anhydrides, and aliphatic, cycloaliphatic or araliphatic diols or mixtures thereof. is the reaction product of Preferred thermoplastic polyester resins include terephthalic acid or a reactive derivative thereof,
aliphatic or cycloaliphatic diols containing 10 carbon atoms by known methods. Also, preferred thermoplastic polyester resins have at least 80
Contains mol %, preferably at least 90 mol %, of terephthalic acid residues and, based on the diol component, at least 80 mol %, preferably at least 90 mol %, of ethylene glycol and/or 1,4-butanediol residues. do. In addition to terephthalic acid residues, thermoplastic polyester resins contain up to 20 mol% of other aromatic dicarboxylic acids containing 8 to 10 carbon atoms or 4 to 10 carbon atoms.
Residues of aliphatic dicarboxylic acids containing 12 carbon atoms, such as phthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, 4,4'-diphenyldicarboxylic acid, succinic acid, adipic acid, sebacic acid It can contain residues of the acids azelaic acid and cyclohexane diacetic acid. In addition to the residues of ethylene glycol or 1,4-butanediol, the thermoplastic polyester resin contains up to 20 mol% of other aliphatic diols containing 3 to 12 carbon atoms or 6 to 21 carbon atoms. residue of a cycloaliphatic diol containing 1,3-
Propanediol, 2-ethyl-1,3-propanediol, neopentyl glycol, 1,5-
pentanediol, 1,6-hexanediol,
Cyclohexane-1,4-dimethanol, 3-methyl-2,4-pentanediol, 2-methyl-
2,4-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 2,2,4-
Trimethyl-1,6-pentanediol, 2-ethyl-1,3-hexanediol, 2,2-diethyl-1,3-propanediol, 2,5-hexanediol, 1,4-di-(β-hydroxy ethoxy)-benzene, 2,2-bis-(4-hydroxycyclohexyl)-propane, 2,4-dihydroxy-1,1,3,3-tetramethylcyclobutane, 2,2-bis-(3-β-hydroxy It can contain residues of ethoxyphenyl)-propane and 2,2-bis-(4-hydroxypropoxyphenyl)-propane. Thermoplastic polyester resins can be branched by incorporating relatively small amounts of trihydric or tetrahydric alcohols or tribasic or tetrabasic carboxylic acids. Examples of preferred branching agents are trimesic acid, trimellitic acid, trimethylolethane, trimethylolpropane and pentaerythritol. Based on acid content, 1 mol%
It is appropriate to use no more branching agents. Particularly preferred thermoplastic polyester resins are:
Polyalkylene terephthalates prepared exclusively from terephthalic acid and its reactive derivatives, such as dialkyl esters and ethylene glycol and/or 1,4-butanediol,
and/or a mixture of these polyalkylene terephthalates. Particularly preferred thermoplastic polyester resins also include copolyesters prepared from at least two of the aforementioned acid components and/or at least two of the aforementioned alcohol components;
(ethylene glycol/1,4-butanediol)
-Terephthalates may be mentioned. The rubbery backbone polymer mainly composed of conjugated diolefin in the present invention is esterified with polybutadiene or other α,β-ethylenically unsaturated monomers other than butadiene, such as styrene, acrylonitrile, and alcohols having 1 to 4 carbon atoms. It is a butadiene-based copolymer obtained by copolymerizing acrylic ester or methacrylic ester. A preferred backbone polymer is pure polybutadiene. The proportion of the rubbery backbone polymer in the graft copolymer of the present invention is 40 to 95% by weight,
Preferably 50 to 90% by weight, more preferably 60 to 90% by weight
If the proportion of the backbone polymer in the graft copolymer is less than 40% by weight, the effect of improving the impact of polyalkylene terephthalate, which is the object of the present invention, will be insufficient, while if it exceeds 95% by weight. Since the compatibility between the thermoplastic polyester resin and the thermoplastic polyester resin deteriorates, mechanical properties such as impact strength and heat resistance deteriorate, which is undesirable. The graft monomer used in the present invention is a mixture of three types: acrylonitrile, aromatic vinyl, and acrylic ester, and among these, acrylic ester preferably has 1 carbon atom.
It contains an alkyl group formed by esterifying ~6 alcohols, and is selected in consideration of copolymerization reactivity with two other types of graft monomers. Moreover, styrene is preferable as the aromatic vinyl. Preferred grafting monomers are those consisting of acrylonitrile, styrene and methyl acrylate. The weight ratio of each monomer in the graft monomer in the present invention is acrylonitrile: aromatic vinyl: acrylic ester = 5-50:20-60:20
-60, preferably acrylonitrile; aromatic vinyl; acrylic ester = 15-40:20-
45: 30-55, more preferably acrylonitrile: aromatic vinyl: acrylic ester = 20-
35:25-40:35-55. If the acrylonitrile content is outside this range, the impact strength will be reduced and the composition will be colored, and if the aromatic vinyl content is outside this range, the physical properties will also deteriorate, which is not preferable. Furthermore, if the acrylic ester content is outside this range, it is also undesirable because the heat resistance and impact strength of the composition decrease. In addition to acrylonitrile, aromatic vinyl, and acrylic acid esters, the graft monomers used in the present invention include other vinyl monomers copolymerizable with these, such as vinyl chloride, vinylidene chloride, vinyl acetate, vinyl propionate, methacrylic acid, and esters thereof. may be included in small amounts. The graft copolymer in the present invention is produced by polymerizing the graft monomer in a latex of polybutadiene or butadiene copolymer using a radical-forming polymerization initiator by a known method, for example, an emulsion polymerization method or a latex suspension polymerization method, and then coagulating and drying. It is obtained by doing. Of course, the present invention can employ various other manufacturing methods, and is not limited to a specific manufacturing method. In the present invention, the blending ratio of the polyalkylene terephthalate and the graft copolymer is 5 to 50 parts by weight, preferably 15 to 45 parts by weight, to 95 to 50 parts by weight of the polyalkylene terephthalate.
The amount is preferably 20 to 40 parts by weight. In this case, the sum of both is 100 parts by weight. When the graft copolymer content is less than 5 parts by weight, no significant improvement is observed in the impact strength of the composition, and when it exceeds 50 parts by weight, a decrease in other properties such as heat resistance and rigidity is observed. This is not desirable because it can cause The method of mixing the polyalkylene terephthalate and the graft copolymer of the present invention does not need to be a special method, and the two are mixed using a suitable mixer, such as a ribbon blender, and then fed to an extruder and melt-kneaded.
This is carried out by the usual method of extruding a string into a molding material by cooling and cutting it. The temperature during the preparation of the mixture is at least 10 °C above the melting point of the polyalkylene terephthalate, and 300 °C
℃ or less, preferably 240 to 280℃. Various additives such as stabilizers, colorants, blowing agents, flame retardants, reinforcing materials such as glass fibers, and fillers may be added to the composition of the present invention to improve performance.
It improves workability, prevents deterioration, and is used as an industrial material.
Alternatively, various performances can be provided as a product. The method of mixing these various additives is not particularly limited either. The composition of the present invention is useful as an industrial material for automobile parts such as bumpers, exterior covers for gasoline tank inlets, spoilers, and parts for electronic and electrical equipment. [Effects of the Invention] The resin composition of the present invention has excellent impact resistance and has well-balanced performance in other mechanical properties, heat resistance, solvent resistance, etc. [Example] The present invention will be further explained with reference to Examples below. Example 1 Polybutadiene latex 80% (solid content equivalent,
Acrylonitrile 5
% and styrene 5% and methyl acrylate 10%
The graft copolymer powder obtained by graft polymerization in an emulsified state and coagulation drying was converted into polybutylene terephthalate (PBT, intrinsic viscosity number [η] = 1.13, measured at 30°C in phenol/tetrachloroethane = 6/4).
The mixture was mixed at the predetermined ratio shown in Table 1 and kneaded and extruded using a 40φ extruder equipped with a Dalmage screw to form pellets. Further, after drying the pellets by heating, a molded product was molded using an in-line screw type 3-ounce injection molding machine (manufactured by Toshiba Machinery Co., Ltd.), and its physical properties were measured. The results are shown in Table 1, and even when the graft copolymer content in the mixture was 10%, the mixture had high impact strength, and as the graft copolymer content increased, the impact strength of the mixture increased. It can be seen that the results are dramatically improved, and the effect is especially surprising in the low temperature range (-40°C).

【table】

[Table] Comparative Example 1 The polybutylene terephthalate used in Example 1 was molded in the same manner as in Example 1, and its physical properties were measured. -40℃) 2Kg・
It was cm/cm. From this, it can be seen that even when the mixture of Example 1 has a low graft copolymer blending ratio, it is greatly improved, especially in impact strength up to -40°C. Comparative Example 2 The same procedure as in Example 1 was carried out except that the blending ratio of the graft copolymer in the composition was 60%. The notched izot impact strength of the composition is 90Kg・cm/cm at room temperature.
cm, 88Kg・cm/cm at low temperature (-40℃), bending strength 300Kg/cm ² , bending modulus 0.7×10 ⁴ Kg/cm ² , heat distortion temperature (4.6Kg/cm ² under load) 118℃ It can be seen that physical properties other than impact strength deteriorate significantly. Example 2 Using the same polybutadiene latex as in Example 1 and keeping the weight ratio of acrylonitrile/styrene/methyl acrylate constant at 25/25/50, graft copolymers with different polybutadiene contents as shown in Table 2 were made. The impact strength of a composition containing 30 parts by weight of the graft copolymer and 70 parts by weight of polybutylene terephthalate (PBT) was measured according to Example 1, and the results are shown in Table 2.

[Table] Comparative Example 3 The same procedure as Example 2 was carried out except that the rubber content in the graft copolymer was changed to 30%. The notched Izo impact strength of the composition was 38 Kg·cm/cm, which shows that the impact strength is extremely lower than that of the composition of Example 2. Comparative Example 4 The same procedure as in Example 2 was carried out except that the rubber content in the graft copolymer was 98%. The notched Izo impact strength of the composition was 32 kg·cm/cm, which shows that the impact strength is significantly lower than that of the composition of Example 2. Example 3 Composition of a graft copolymer (30 parts by weight) containing 80% of a rubbery component and having different compositions of the rubbery component and graft monomer as shown in Table 3 and polybutylene terephthalate (70 parts by weight) A product was manufactured according to Example 1, and the impact strength and heat distortion temperature (4.6
Kg/ ^cm2 under load) was measured.

[Table] No. 1 to No. 5 are graft copolymers having polybutadiene as the backbone polymer but with different ratios of graft monomers, and No. 4 is the same as the composition of Example 1. No. 6 uses SBR (styrene/butadiene = 25/
This is an example corresponding to the present invention using No. 75).
7 is NBR (acrylonitrile/butadiene = 35/
This is an example corresponding to the present invention using 65). As is clear from the results of Nos. 1 to 5, it can be seen that as the ratio of methyl acrylate increases, the heat distortion temperature, which is a major feature of the mixtures of the present invention, increases. Example 4 According to Example 1, polybutadiene content 80
%, a mixed composition of 30 parts by weight of a graft copolymer with a ratio of acrylonitrile/styrene/methyl acrylate of 25/25/50 and 70 parts by weight of polybutylene terephthalate was prepared, and this was immersed in toluene and styrene for 250 hours. , Notched Izot impact strength was measured, 91Kg・cm/cm (after immersion in toluene), 89Kg・cm/cm (after immersion in toluene)
It was hot. As is clear from the results, the impact strength of the composition of the present invention shows almost no change even after being immersed in a solvent for a long time than before immersion.

Claims (1)

[Claims] 1 40 to 95% by weight of a rubbery backbone polymer mainly composed of conjugated diolefin, consisting of acrylonitrile, aromatic vinyl, and acrylic ester, with a weight ratio of acrylonitrile: aromatic vinyl: acrylic ester = 5 to 50 :20〜
Impact-resistant resin composition prepared by mixing 5-50 parts by weight of a graft copolymer obtained by grafting 60-5% by weight of a monomer mixture with a ratio of 60:20-60 and 95-50 parts by weight of a thermoplastic polyester resin. thing.