JPS61163956A - Polyester resin molding composition - Google Patents

Abstract

PURPOSE:To obtain a molding resin compsn. having improved impact resistance, by blending a graft copolymer, obtd. by grafting maleic anhydride onto an ethylene/unsaturated carboxylate ester copolymer, with a thermoplastic polyester resin. CONSTITUTION:A resin compsn. consists of 60-95wt% thermoplastic polyester resin and 40-5wt% graft copolymer obtd. by grafting 0.1-8wt% maleic anhy dride onto an ethylene/unsaturated carboxylate ester copolymer having an unsatu rated carboxylate content of 4-22mol%. Examples of the thermoplastic polyes ter resins are polyethylene terephthalate and polybutylene terephthalate. 5-60pts. wt. glass fiber may be added to 100pts.wt. compsn. to reinforce it.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polyester resin composition for molding. More specifically, the present invention relates to a polyester resin composition for molding that has significantly improved impact resistance without substantially impairing the desirable properties inherent in thermoplastic polyester resins, such as mechanical and electrical properties and heat resistance.

[Conventional technology]

In general, thermoplastic polyester resins have excellent mechanical and electrical properties, heat resistance, abrasion resistance, and chemical resistance, so they are used as engineering resins for various mechanical parts, electrical insulation materials, automobile parts, etc. Although it has become widely used, there is a problem in that it is not satisfactory in terms of impact resistance.

Furthermore, in order to improve mechanical strength including rigidity and dimensional stability, a method of blending glass fiber is also used, but impact resistance is also insufficient in this case.

In order to compensate for these drawbacks, various modifications of thermoplastic polyester resins by blending with other types of resins have been proposed. For example, a method of blending both an ionomeric terpolymer and a second terpolymer into polyethylene terephthalate (Japanese Unexamined Patent Publication No. 117,559/1982)
, a method of blending an ethylene-glycidyl methacrylate copolymer, glass beads, and the king of glass fibers into a thermoplastic polyester (No. 57-192,455);
A method of blending an ethylene-ethyl acrylate copolymer, an ethylene-vinyl acetate copolymer, or both of these into polybutylene terephthalate (Publication No. 58-45,255) has been proposed, but none of them have good impact resistance. The effect of improving sex is still not sufficient.

[Problem that the invention seeks to solve]

As a result of various studies on methods for improving impact resistance without substantially impairing any of the above-mentioned desirable properties inherent to thermoplastic polyester resins, the present inventors found that using a specific maleic anhydride graft It has been found that this problem can be effectively solved by incorporating a modified product therein.

[Means for Solving the Problem] and [Operation] Accordingly, the present invention relates to a polyester resin composition for molding, which comprises about 60 to 95% by weight of a thermoplastic polyester resin and Co-ethylene-unsaturated carboxylic acid ester with an unsaturated carboxylic acid ester content of 4 to 22 mol%* + n # yk v v 4
> eRt lh O°1~81! t%/5
.

It consists of about 40 to 5% by weight of a graft-modified product copolymerized.

However, this type of polyester resin composition for molding is
It is described in JP-A No. 55-99,945, that is, 70 to 99% by weight, preferably 75 to 97% by weight of an olefinic polymer that may contain an ethylene-unsaturated carboxylic acid ester copolymer is Unsaturated compounds 30-II
1% by weight, preferably 25 to 3% by weight of a graft modified product obtained by graft copolymerization is blended into a thermoplastic polyester,
It is described that a thermoplastic polyester molding material with excellent toughness can be obtained.

Although maleic anhydride is also exemplified as an ethylenically unsaturated compound, it is not mentioned as a particularly preferred ethylenically unsaturated compound. However, anhydrous maleic I! l[! When the t-graft copolymerized nine-graft modified product is blended into a thermoplastic polyester resin, the amount of grafting is lj! It has been found that a sufficient impact resistance improvement effect can be achieved even if the amount is less than % quantum. In addition, in the obtained thermoplastic polyester resin composition, only the maleic anhydride graft modified product was dispersed with a dispersed particle diameter of 15 ltm or less, which effectively achieved the above effect. This is considered to be one of the factors responsible for increasing the affinity and reactivity between the graft modified product and the thermoplastic polyester resin.

Thermoplastic polyester resin modified according to the invention,
! : Polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polypropylene naphthalate, polybutylene naphthalate, and the like.

Examples of the ethylene-unsaturated carboxylic acid ester copolymer which becomes the paste polymer of the graft modified product include ethylene and methyl acrylate, ethyl acrylate, and acrylic rIln.
- butyl, isobutyl acrylate or the corresponding alkyl methacrylate, preferably copolymers with ethyl acrylate or methyl methacrylate,
The unsaturated carboxylic acid ester content used is 4 to 22 mol%, preferably 8 to 20 mol%. If the copolymerization ratio of the unsaturated carboxylic acid ester is higher than this, it will not only be difficult to produce the copolymer, but also the flexural elasticity and heat resistance of the graft modified product will be extremely reduced, and the composition It significantly deteriorates the physical properties when On the other hand, if a copolymerization ratio smaller than this is used,
The effect of improving impact resistance, which is the objective of the present invention, is not achieved.

Oh, that M-work [Melt Index i ASTMD]
-1238 (190°C, 2160 g), unit dg] varies depending on the thermoplastic polyester resin used, but is usually about 0.3 to 300, preferably about 0.5 to
200 is used, and copolymers outside this range are generally difficult to produce.

The amount of maleic anhydride grafted onto such base polymer is in the range of about 0.1 to 8%, preferably about 0.3 to 4% by weight, based on the base polymer. If the amount of grafting is less than this, the above object of the present invention cannot be achieved, whereas if the amount of grafting is more than this, the effect of improving impact resistance will not be increased any further, and on the contrary, it may be used in excess. Maleic anhydride remaining in the graft-modified product sublimes or evaporates at the stage of the graft-modified product, composition, or molded product, giving undesirable results such as poor appearance due to yellowing.

The grafting reaction is carried out according to common methods and is industrially carried out at about 120-250°C in an extruder in the presence of a free radical-generating compound such as tert-butyl peroctoate.
This is done by kneading.

The M engineering of the obtained graft modified product depends on the reaction conditions during graft modification, that is, the type and amount of the free radical generating compound,
Although it varies depending on the temperature, pressure, time and humidity, it is generally within the range of about 0.01 to 100.

The thermoplastic polyester resin composition of the present invention comprises about 60 to 95% by weight of thermoplastic polyester resin, preferably about 70 to 95 fi:'! % and about 40-5% by weight of the maleic anhydride graft modified product, preferably about 30-5% by weight. If the blending ratio of the graft modified product exceeds this range, the favorable properties inherent to the thermoplastic polyester resin in terms of bending elasticity, heat resistance, etc. of the composition will be impaired.On the other hand, if the blending ratio is lower than this, the Impact resistance improvement effect cannot be obtained.

In addition, when an ethylene-vinyl acetate symbiotic polymer, which is generally used equally with an ethylene-unsaturated carboxylic acid ester copolymer, is used as a base polymer, its maleic anhydride graft modified product is melted with a thermoplastic polyester. During kneading and molding of the kneaded product, deacetic acid reaction occurs from the base polymer, which causes smoke and deteriorates the working environment during melt-kneading, and during molding, not only causes mold corrosion but also improves impact resistance. No effect can be obtained. In addition, even when an ethylene-unsaturated carboxylic acid ester copolymer is used as the base polymer, the graft modified product using acrylic acid or acrylic ester instead of maleic anhydride has a high resistance to No impact improvement effect can be obtained.

Glass fibers may be incorporated into the composition comprising the thermoplastic polyester resin and the maleic anhydride graft modified product in an amount of about 5 to 60 parts by weight per 100 parts by weight of the composition for reinforcement. For the purpose of reinforcement, K is required to be blended in at least this amount; on the other hand, if it is used in a higher proportion, it not only becomes difficult to blend, but also reduces the impact resistance.

Glass fibers that are surface-treated with a silane coupling agent such as aminosilane or vinylsilane are generally used, and the dimensions can be selected arbitrarily, but generally the fiber length is about 2 to 7 ml and the fiber diameter is 5 to 20 μm. is used.

The composition is prepared by triblending or melt blending the necessary components of each of the above components.

In the case of a triblend, each component is uniformly melt-mixed at the stage of being plasticized in a molding machine. In the case of melt blending, melt mixing may be performed using various mixers such as a single-screw extruder, twin-screw extruder, Banbury mixer, rolls, kneaders, and the like.

In addition, when preparing the composition, talc,
Inorganic fillers such as silica and calcium carbonate, heat stabilizers,
It is possible to add UV absorbers, pigments, etc. as appropriate.

〔Effect of the invention〕

The thermoplastic polyester resin composition for molding according to the present invention significantly improves impact resistance without substantially impairing the desirable properties inherent in thermoplastic polyester resins, and has the quality required industrially. It has a clear bending elastic modulus of 1000 MPa or more at 23° C. and an Izot impact strength of 70 J/m or more.

Therefore, this composition can be used in the molding field of most plastic processing techniques such as film molding, injection molding, blow molding, and profile extrusion molding by effectively utilizing such properties.

〔Example〕

Next, the present invention f will be explained with reference to an example.

Example 1 Polybutylene terephthalate resin (Toshi PBT m resin 1
401-xo6) 80 parts (by weight, same hereinafter) and anhydrous male "-"
'Mf7 degenerate (Graph 1-io, 3111%)
20 parts were melt-kneaded at 250°C using a twin-screw extruder (30 warp resistance, coaxial rotation), and the resulting polyester resin composition was molded at 260°C and at a whole mold temperature of F2.
A test piece was injection molded at 0t:.

The following physical property values were measured for this test piece.

Izot impact strength: ASTM D-256 compliant thickness 5. nIn, y-notched, 23°C bending elastic modulus: A
STM D-790 compliant, 2M injection square plate heat resistance; 2.1
Frl injection angle, heated at 1290 °C for 1 hour, and measured the difference in heat shrinkage rate (shrinkage rate after heating - molding shrinkage rate) Dispersed particle size of graft modified product: A heated press sheet was prepared and polyester matrix [medium] Observation of the dispersed particle diameter of the modified product using an IVA electron microscope (Hitachi H-500H) Examples 2 to 3 In Example 1, 1.0% by weight of the modified product (Example 2) or 2.0% by weight (Example 3) of the maleic anhydride graft modified product were used, respectively.

Example 4 In Example 1, other ethylene-ethyl acrylate copolymer (containing ethyl acrylate) was used as the base polymer.
K t 15.7 mol %, Mf) was used.

Examples 5 to 6 In Example 3, the blending amount of the polybutylene terephthalate resin was 90 tflS (Example 5) or 60 parts (Example 6), and the blending amount of the maleic anhydride graft modified product was correspondingly changed. The number was changed to 10 or 40 copies, respectively.

Example 7 In Example 3, 15 parts of glass fiber (Nitto Boseki product, fiber length 6.11, fiber diameter 13 μm) was further blended to prepare a composition.

The same physical property values as in Example 1 were also measured for Examples 2 to 7 above.

Comparative Example 1 The physical properties of the polybutylene terephthalate resin used in Example 1 were measured at all times.

Comparative Example 2 In Example 1, maleic anhydride graph)! Instead of the polymer, a combination of ethylene and ethyl acrylate, which is its base polymer, was used.

Comparative Example 3 In Example 1, Zn ion-crosslinked ionomer resin of ethylene-methacrylic acid copolymer (methacrylic acid N content 4.5 mol%, M engineering 13.5) was used instead of the maleic anhydride graft modified product. Ionization i40%) was used.

Comparative Example 4 In Example 1, instead of the anhydrous maleic bush graft modified product, ethylene-methacrylic acid-isobutyl acrylate ternary copolymer (meccrylic acid content Mt 4.0 mol%, isobutyl acrylate content J content Z 5 mol%) , M engineering 35) Zn
Ionized ionomer packing fat (ionized IE?70%)
was used.

Comparative Example 5 In Example 1, an ethylene-methacrylic acid-isobutyl acrylate terpolymer (containing methacrylic acid (i 4.0 mol%,
Contains isobutyl acrylate 1J12.5 mol%, M engineering 10
) was used.

Comparative Examples 6 to 7 = m In Example 1, ethylene-vinyl acetate copolymer (vinyl acetate content 9.9 mol%, M
Graft amount 0.3% by weight (Comparative Example 6) or 1
．． A graft modified product obtained by completely graft copolymerizing maleic anhydride at 0% by weight (Comparative Example 7) was used.

Comparative Example 8 In Example 1, ethyl was used as the graft modified product.
Ethyl acrylate copolymer (ethyl acrylate content 8
．． A tertiary butyl acrylate graft modified product (grafting amount: 5 mole %, M engineering 5) was used.

Comparative Example 9 In Example 1, an acrylic acid graft-modified ethylene-ethyl acrylate copolymer (Graph tO, 31 m%) was used as the graft modified product.

The same physical property values as in Example 1 were also measured for Comparative Examples 2 to 9 above.

Buttocks Example 1 0.9 121 17
10#2 #165
1700#30.8 (not destroyed) 1700#
40.6 (without destruction) 1640#
5 0.8 117 20
5016 〃 (Do not destroy) 10
50 Comparative Example 1-24 2
200#25 58 17
00#3 L, 5 45
180014 LO301710 #5 #41
1600t6 0.5 55
1700I? 0.3 7
0 170ONB 0.9
62 1600#9 LO70
1650

Claims (1)

[Claims] 1. About 0.0% of maleic anhydride is added to a thermoplastic polyester resin of about 60 to 95% by weight and an ethylene-unsaturated carboxylic acid ester copolymer having an unsaturated carboxylic acid ester content of 4 to 22% by mole. A molding polyester resin composition comprising about 40 to 5% by weight of a graft modified product obtained by graft copolymerization of 1 to 8% by weight. 2. The polyester resin composition for molding according to claim 1, wherein the thermoplastic polyester resin is polybutylene terephthalate. 3. The polyester resin composition for molding according to claim 1, in which a graft modified product having a particle size of about 15 μm or less is dispersed. 4. Grafting about 0.1 to 8% by weight of maleic anhydride to a thermoplastic polyester resin of about 60 to 95% by weight and an ethylene-unsaturated carboxylic acid ester copolymer having an unsaturated carboxylic acid ester content of 4 to 22 mol%. A molding polyester resin composition comprising about 5 to 60 parts by weight of glass fiber per 100 parts by weight of a composition comprising about 40 to 5% by weight of a copolymerized graft modified product. 5. The polyester resin composition for molding according to claim 4, wherein the thermoplastic polyester resin is polybutylene terephthalate. 6. The polyester resin composition for molding according to claim 4, in which a graft modified product having a particle size of about 15 μm or less is dispersed.