JP2786477B2 - Polyethylene terephthalate resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a polyethylene terephthalate resin composition having improved moldability that provides stable molded article properties even when a small amount of moisture is present during molding. .

(Prior Art) Polyethylene terephthalate resin is widely used in various industrial fields as an engineering plastic having excellent mechanical and physical properties. However, since polyethylene terephthalate resin is a polyester resin having a high melting point, hydrolysis occurs in a very short time due to a small amount of moisture contained in the pellets or adhered to the surface of the pellets during the molding process. It has the drawbacks of significantly reducing the mechanical and physical properties of the product and generating "burrs" on the product parting line.

In order to solve the drawbacks of the polyethylene terephthalate resin, many techniques for blending an epoxy resin or a phosphorus-based stabilizer have been reported, but they have not been completely solved.

(Problems to be Solved by the Invention) Therefore, when molding a polyethylene terephthalate resin, the pellets are sufficiently dried before the molding, the moisture content is reduced to 100 to 200 ppm or less, and supplied to the molding machine for a short time. It is necessary to end the operation by heating and melting at. For management of such troublesome pellet moisture and molding conditions,
Although the polyethylene terephthalate resin has excellent mechanical and physical properties as compared with the polybutylene terephthalate resin, the market expansion is currently delayed.

The present inventors have conducted intensive studies to solve the problems of these polyethylene terephthalate resin compositions, and have reached the present invention.

(Means for Solving the Problems) The present inventor has found that when a specific epoxy resin and a polystyrene-based resin are combined with a polyethylene terephthalate resin within a specific range, extremely stable moldability is obtained even when water is contained. Was found.

That is, the present invention is a polyethylene terephthalate resin composition comprising the following components and composition ratios.

(A) 100 parts by weight of polyethylene terephthalate, (B) 1 to 15 parts by weight of a bisphenol type epoxy resin having an epoxy equivalent of 1000 or less, (C) 3 or more epoxy groups in one molecule, and an epoxy equivalent of 350 to 2500. (D) 5 to 50 parts by weight of a polystyrene resin, and (E) 5 to 150 parts by weight of glass fiber.

Component (A): As the polyethylene terephthalate resin of the component (A) used in the present invention, terephthalic acid or an ester-forming derivative thereof is used as an acid component, and ethylene glycol or an ester-forming derivative thereof is used as a glycol component. A polymer that has been polycondensed. In this case, each of the acid component and the glycol component may contain 20 mol% or less of other dicarboxylic acids, glycols, or ester-forming derivatives thereof. Such other types of copolymerization components include, for example, dicarboxylic acids such as isophthalic acid, naphthalene-2,6-dicarboxylic acid, and adipic acid; trimethylene glycol, tetramethylene glycol, neopentyl glycol, hexamethylene glycol, diethylene glycol, Glycols such as cyclohexanediol, 1,4-bis (oxyethoxy) benzene, bisphenol A, polyethylene glycol and polypropylene glycol, and ester-forming derivatives thereof can be mentioned.

The intrinsic viscosity of the polyethylene terephthalate resin used in the present invention is 0.4% when measured at 23 ° C. using a 1: 1 weight ratio mixture of phenol and tetrachloroethane as a solvent.
It is desirably in the range of 1.2 to 1.2 dl / g, particularly 0.5 to 0.8 dl / g. When a polyethylene terephthalate resin having an intrinsic viscosity of less than 0.4 dl / g is used, not only is the effect of improving the "burrs" of the molded product small, but also the strength of the obtained molded product is low and not practical. Further, when polyethylene terephthalate having an intrinsic viscosity of more than 1.2 dl / g is used, the fluidity of the composition is extremely poor and the gloss of the appearance of the obtained molded product is unfavorably lost.

Component (B): The bisphenol-type epoxy resin, which is the component (B) used in the present invention, preferably has an epoxy equivalent of 1,000 or less. For example, a bisphenol A type epoxy resin obtained by reacting bisphenol A with epichlorohydrin is suitable.

Component (C): The epoxy resin used as the component (C) in the present invention is an epoxy resin having three or more epoxy groups in one molecule and having an epoxy equivalent of 350 to 2500. For example, styrene-glycidyl (meth) acrylate copolymer, styrene-glycidyl (meth) acrylate-methyl (meth) acrylate terpolymer, styrene-glycidyl (meth) acrylate-methyl (meth) acrylate-
Polymers obtained by radical copolymerization of various vinyl compounds such as styrene, glycidyl (meth) acrylate, acrylate, acrylonitrile, and vinyl acetate, such as acrylonitrile quaternary copolymer, ethylene-vinyl acetate-glycidyl (meth) acrylate Examples include a terpolymer, a novolak epoxy resin obtained from a novolak resin and epichlorohydrin, and the like. Among these epoxy resins, binary to quaternary copolymers containing styrene and glycidyl (meth) acrylate are preferred.

Component (D): The polystyrene resin as the component (D) used in the present invention includes, in addition to a normal styrene resin and a high-impact polystyrene resin, an acrylonitrile-styrene copolymer having a styrene content of 50 mol% or more, acrylonitrile -Styrene-butadiene copolymers are also included. Of these, high impact polystyrene resin is particularly preferred.

Component (E): The glass fiber as the component (E) used in the present invention is not particularly limited as long as it is generally used for resin reinforcement. For example, a long fiber type (roving) or a short fiber type (chopped strand) can be selected and used. The glass fibers may be treated with a sizing agent (eg, polyvinyl acetate, polyester, etc.), a coupling agent (eg, a silane compound, a borane compound, etc.), and other surface treatment agents.

Blending ratio: The blending amount of the bisphenol type epoxy resin (B) is 1 to 15 parts by weight, preferably 2 to 12 parts by weight, more preferably 3 to 10 parts by weight based on 100 parts by weight of the polyethylene terephthalate resin (A). is there. If the amount is less than 1 part by weight, the effect of the present invention is small.
And the mechanical strength decreases.

The compounding amount of the epoxy resin (C) having three or more epoxy groups in one molecule is 1 to 15 parts by weight, preferably 2 to 100 parts by weight of the polyethylene terephthalate resin (A).
To 12 parts by weight, more preferably 3 to 10 parts by weight. When the amount is less than 1 part by weight, the effect of the present invention is small. On the other hand, when the amount is more than 15 parts by weight, the fluidity of the composition is extremely poor and is not practical.

Further, it has been found that when the mixing ratio of the above components (B) and (C) satisfies the following formula, good results can be obtained in the properties of the resin composition.

The amount of the polystyrene resin (D) is 5 to 50 parts by weight, preferably 7 to 40 parts by weight, more preferably 8 to 30 parts by weight, based on 100 parts by weight of the polyethylene terephthalate resin (A).
Parts by weight. If the amount is less than 5 parts by weight, the effect of the present invention is small, and if it is more than 50 parts by weight, heat resistance and mechanical strength are significantly reduced.

The amount of the glass fiber (E) is 5 to 150 parts by weight, preferably 10 to 130 parts by weight, based on 100 parts by weight of the polyethylene terephthalate resin (A). If the amount is less than 5 parts by weight, the reinforcing effect by the glass fiber is insufficient, and if it is more than 150 parts by weight, the fluidity and appearance of the composition are significantly deteriorated.

Mixing / kneading: Preparation of the composition of the present invention is carried out by a usual mixer / kneader. That is, after each component is charged into a V blender, a ribbon mixer, a tumbler, or the like and uniformly mixed,
The mixture is melt-kneaded by a conventional single-screw or twin-screw extruder, cooled, and cut into pellets. At this time, a part of the glass fiber and other components may be added in the middle of the extruder. Alternatively, after some of the components are previously mixed and kneaded, the remaining components may be added and extruded.

The composition of the present invention may contain a flame retardant (for example, brominated bisphenol ale, brominated epoxy resin, brominated polystyrene resin, brominated polycarbonate resin, triphenyl phosphate, phosphonic acid, as long as the object of the present invention is not impaired. Amides, red phosphorus, etc.), flame retardant aids (eg, antimony trioxide, sodium antimonate, etc.), inorganic fillers (eg, calcium carbonate, silica, talc, mica, potassium silicate, potassium titanate, etc.), Nucleating agents (eg, sodium stearate, ethylene-sodium acrylate copolymer, etc.), stabilizers (eg, phosphate esters,
Phosphites), antioxidants (eg, hindered phenol compounds), light stabilizers, coloring agents, foaming agents,
A lubricant, a release agent, an antistatic agent and the like may be blended.

In addition, a small amount of other thermoplastic resins (eg, polyethylene, polypropylene, polyamide resin, polycarbonate resin, polyphenylene ether resin, polyphenylene sulfide resin, etc.), thermosetting resins (eg, phenolic resin, melamine resin, silicone resin, etc.), A soft thermoplastic resin (for example, ethylene-propylene terpolymer, ethylene-vinyl acetate copolymer, polyester elastomer, etc.) may be added.

The composition thus obtained can be easily molded by any method such as injection molding, extrusion molding, compression molding or rotational molding.

(Example) Example 1 and Comparative Examples 1 to 7 For polyethylene terephthalate (PET) having an intrinsic viscosity of 0.7 dl / g (a phenol: tetrachloroethane 1: 1 mixed solvent, measured at 23 ° C.) as a component (A). , Epicoat 828 (manufactured by Yuka Shell Co., epoxy equivalent 19
0), Blenmer CP15 (manufactured by NOF CORPORATION, epoxy equivalent: 1000) as the component (C), Dialex HT76 (manufactured by Mitsubishi Monsanto, high impact polystyrene, HIPS) as the component (D), and glass fiber T198H as the component (E)
(Manufactured by Nippon Electric Glass Co., Ltd.) in a mixing ratio of 10 l using a 10-liter tumbler, then melt-kneaded at a cylinder temperature of 260 ° C. using a vented single-screw extruder with a screw diameter of 40 mmφ, and formed pellets by strand cutting. Obtained. The moisture content of the pellets was changed to about 100, 5
After adjusting to three levels of 00 and 1500 ppm, molding was performed using a 6 oz. Injection molding machine (N-100BII manufactured by Nippon Steel Works) at a cylinder set temperature of 265 ° C, a mold temperature of 90 ° C, a cooling time of 20 seconds, and a total molding cycle of 35 seconds. A test piece was obtained. In addition, the injection pressure was unified to the optimum pressure at which "burrs" did not occur when 100 ppm water content pellets of the same composition were molded.

 The occurrence of "burrs" was evaluated in the following four stages.

×: Appears all around the test piece.

Δ: The degree is small, but observed all around.

：: Only observed near the gate.

：: Not recognized.

The measurement of tensile strength and Izod (non-notch) impact strength was based on JIS K7113 and K7110, and the results are shown in Table 1.

From Table 1, it can be seen that the compositions of Examples are composed of the components (B) and (C).
Compared to Comparative Examples 1 to 7, which lacked at least one of (D), even when molded in a water-containing state of 1500 ppm, there was almost no decrease in mechanical strength and generation of "burrs" was extremely small.

Examples 2 to 7 and Comparative Examples 8 to 13 The same kinds of raw materials as in Example 1 were used, and only the mixing ratio of the components (B) and (C) was changed. The mixing, kneading, molding, and evaluation of the raw materials were performed in the same manner as in Example 1. The results are summarized in Table 2. Table 2 shows that the effect of the present invention is not recognized when the blending amount of Epicoat E828 or Blemmer CP15 is 1 part by weight or less with respect to PET. On the other hand, when E828 or CP15 was 15 parts by weight or more, the mechanical strength of the composition was lowered or the melt viscosity was remarkably increased, and molding was impossible. Also, E828 / C
When the ratio of P15 was 0.2 or less (Comparative Example 12), the composition was extremely poor in melt fluidity and molding was impossible. On the other hand, three or more (Comparative Example 13) had less effects of the present invention than Examples 1 to 7.

Examples 8 to 10 and Comparative Examples 14 to 15 Using the same type of raw materials as in Example 1, only the mixing ratio of the components (D) and (E) was changed. The mixing, kneading, molding, and evaluation of the raw materials were performed in the same manner as in Example 1. The results are summarized in Table 3. According to the table, when the blending amount of HT76 is less than 5 parts by weight, the effect of the present invention is not recognized. When the blending amount is more than 50 parts by weight, the reduction due to moisture of the pellet is not recognized, but the mechanical strength itself is remarkably reduced and is not practical.

Examples 11 to 13 and Comparative Examples 16 to 17 The same kinds of raw materials as in Example 1 were used, and only the mixing ratio of the component (E) was changed. The mixing, kneading, molding, and evaluation of the raw materials were performed in the same manner as in Example 1. The results are summarized in Table 4. As shown in the table, when the blending amount of the glass fiber was 5 parts by weight or less, the mechanical strength was low, and when it was 150 parts by weight or more, the melt viscosity of the composition was high and molding was impossible. In Comparative Example 17, molding was possible at the maximum injection pressure only when the pellets contained 1480 ppm of water.

Examples 14 and 15 and Comparative Example 18 The same experiment as in Example 1 was performed using bisphenol A type epoxy resins having different epoxy equivalents as the component (B). The results were compared with Example 1 and summarized in Table 5. From the table, the epoxy equivalent of bisphenol A type epoxy resin is
It turns out that the effect of the present invention is not recognized when it exceeds 1,000.

Example 16 and Comparative Examples 19 and 20 The same experiment as in Example 1 was performed using epoxy resins having different epoxy equivalents as the component (C). The results were compared with Example 1 and summarized in Table 6. As shown in the table, when the epoxy equivalent of the epoxy resin (C) was 350 or less, the melt flowability of the composition was poor and molding was impossible. Further, at 2500 or more, the effect of the present invention was not recognized.

Examples 17 and 18 Taflex 710 (Acrylonitrile-butadiene-styrene copolymer, ABS, manufactured by Mitsubishi Monsanto Co., Ltd.) as styrene resin as component (D), Sunlex SAN-
The same experiment as in Example 1 was performed using A (Acrylonitrile-Styrene Copolymer, manufactured by Mitsubishi Monsanto Co., Ltd.). The results are shown in Table 7 along with Comparative Example 5. From the table, it was confirmed that both resins exhibited the same effects as in Example 1.

(Effect of the Invention) The polyethylene terephthalate resin composition of the present invention comprises:
As mentioned above, even if a small amount of water is present during molding,
Deterioration during molding is hardly observed, flow characteristics are good,
Shows stable moldability. For this reason, the occurrence of burrs on the molded product is minimized, and a molded product with less deterioration in mechanical and physical properties is obtained. In addition, strict control of moisture such as prevention of moisture absorption and strict control of molding conditions as in the case of conventional molding materials can be greatly eased.

────────────────────────────────────────────────── (5) Continuation of the front page (51) Int.Cl. ⁶ identification code FI C08L 25:00) (56) References JP-A-59-129253 (JP, A) JP-A-61-261346 (JP, A) (58) Field surveyed (Int.Cl. ⁶ , DB name) C08L 67 / 02,63 / 00-63/10 C08K 7/14

Claims (1)

(57) [Claims] 1. A polyethylene terephthalate resin composition comprising the following components and composition ratios: (A) 100 parts by weight of polyethylene terephthalate; (B) 1 to 15 parts by weight of a bisphenol type epoxy resin having an epoxy equivalent of 1,000 or less; (C) 1 to 15 parts by weight of an epoxy resin containing 3 or more epoxy groups in one molecule and having an epoxy equivalent of 350 to 2500; (D) 5 to 50 parts by weight of a polystyrene resin; and (E) glass fiber of 5 to 150 parts. Parts by weight.