JPH062868B2 - Polyester composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a polyester composition which gives a molded article having excellent mold releasability, surface characteristics and physical properties in low temperature mold molding, and various molded articles, sheet-shaped articles, It can be widely used for forming tubular products, laminates, containers, etc., but it also has excellent electrical resistance and heat stability.
It is particularly effectively used for molding sockets, connector relays, fuse parts, motor parts, range parts, IC parts and the like.

[Conventional technology]

Polyethylene terephthalate is excellent in heat resistance, chemical resistance, mechanical properties, electrical properties, etc., and is used in many industrial chemicals as fibers and films. However, when it is used for plastics as an injection molded product, many defects are observed in molding due to the special crystallization behavior of polyethylene terephthalate. Polyethylene terephthalate is a crystalline polymer by nature, but because of its high second-order transition point, when molded at a mold temperature of 100 ° C. or lower, which is usually carried out by a general molding machine for general-purpose thermoplastic resins. The shape stability of the molded product at the temperature of the second-order transition point or higher remarkably deteriorates. In addition, the releasability is poor and a long cycle time is required. To improve such defects, increase the crystallization rate of polyethylene terephthalate,
It is necessary to shift the crystallization start temperature to a low temperature side and promote crystallization sufficiently to the surface layer of the molded product. To increase the crystallization rate, nucleating agents, especially talc, carboxylic acid metal salts, ionomers, etc. are generally added, but even if the amount is increased, the target mold temperature of 100 ° C. or lower is used. It is not possible to obtain sufficient effect to obtain sufficient moldability and physical properties at temperature, and it is particularly difficult to shift the crystallization start temperature to the low temperature side, and crystallization of the surface layer of the molded product in the low temperature mold is difficult. Totally insufficient.

Presently, JP-A-54-148833 and JP-A-54-
As can be seen in JP-A-139654, JP-A-54-158452, and JP-A-53-90360,
A method is known in which an additive having a plasticizing effect is blended to shift the crystallization start temperature to a low temperature side.

However, these additives have the drawbacks of being gasified during molding and contaminating the surface of the molded product, causing gas burn at the weld, and bleeding on the surface of the molded product during use. . Additives that react with the ends of the polyester are also known, as in JP-A-54-150458, but the blending amount is limited due to the reaction equivalence.
Not enough effect has been obtained.

[Problems to be solved by the invention]

The present invention has various problems in the above-mentioned prior art, that is, the additive compounded to shift the crystallization initiation temperature of polyethylene terephthalate to the low temperature side is gasified during molding and bleed out during use. It solves the problem.

[Means for solving problems]

The present inventors have finally made the present invention as a result of diligent research and efforts to solve the above problems. That is, in the present invention, a polymer obtained from a monomer having a vinyl group is used as a trunk polymer in 100 parts by weight of polyester in which 80 mol% or more of repeating units are ethylene terephthalate, and a polyether residue having a molecular weight of 90 to 5000 and /
Alternatively, a polyester composition containing 0.5 to 80 parts by weight of a graft polymer having an aliphatic polyester residue as a side chain, wherein the monomer having a vinyl group forming the trunk polymer is styrene, acrylonitrile, vinyl acetate, The polyester composition is one or more selected from acrylic acid ester, methacrylic acid ester, ethylene, propylene, butylene, acrylic acid, methacrylic acid, glycidyl methacrylate, and butadiene.

As the ethylene terephthalate polyester used in the present invention, not only polyethylene terephthalate but also at least 80 mol% or more, preferably 90 mol%
Copolymerized polyesters containing the above ethylene terephthalate repeating units may be mentioned. A known acid component and / or glycol component can be used as the copolymerization component. That is, examples of the copolymerization component include acid components such as isophthalic acid, naphthalene 1,4 or 2,6 dicarboxylic acid, diphenyl ether 4,4 'digalbonic acid, adipic acid and sebacic acid, propylene glycol, butylene glycol, diethylene glycol. , Neopentyl glycol, cyclohexanedimethanol, glycol components such as 2,2′bis (4-hydroxyphenyl) propane, oxyacids such as p-oxybenzoic acid and p-hydroxyethoxybenzoic acid, and the like. The polyester is a phenol / tetrachloroethane mixed solution (6 /
(4 weight ratio), the intrinsic viscosity obtained by measuring at 30 ° C. is 0.4 or more, preferably 0.5 or more. Needless to say, the polyester may be a combination of two or more kinds.

Next, the molecular weight of 90 to 5,000 to be added to the composition of the present invention.
A polymer having a polyether residue and / or an aliphatic polyester residue as a side chain is a monomer having a vinyl group and a polyether residue or an aliphatic polyester residue in the molecule (hereinafter referred to as a graft chain monomer)
Or a monomer having another vinyl group as a copolymerization component, or a monomer having the other vinyl group is previously polymerized to form a trunk polymer, and the graft chain monomer is subjected to organic peroxide. It can be obtained by adopting a method in which it is allowed to act with an object or radiation and introduced into the trunk polymer.

Specific examples of the graft chain monomer include polyethylene glycol monomethacrylate, polyethylene glycol monoacrylate, polyethylene glycol dimetalylate, polyethylene glycol diacrylate, polylactone monomethacrylate polylactone monoallylate, polylactone dimethacrylate, and polylactone. Dimethacrylate, polyethylene adipate monomethacrylate, polyethylene adipate monoacrylate, polyethylene adipate dimethacrylate, polyethylene adipate diacrylate, polybutylene adipate monomethacrylate, polybutylene adipate monoacrylate, polybutylene adipate dimethacrylate, polybutylene adipate diacrylate, polypropylene glycol Bruno methacrylate, polypropylene glycol monoacrylate, polypropylene glycol dimethacrylate, polypropylene glycol diacrylate or glycidyl etherifying the terminal hydroxyl groups of the monomethacrylate and monoacrylate,
Examples thereof include etherified, esterified, and urethane-ized derivatives. Among them, polyethylene glycol monomethacrylate, polyethylene glycol monoacrylate,
Preferred compounds include polylactone monomethacrylate, polylactone monoacrylate and the like and derivatives thereof. However, the molecular weight of the polyether residue or the aliphatic polyester residue as the graft chain is 90.
Is preferably 5,000, more preferably 100 to 20.
It is particularly preferable that it is about 00. If the molecular weight is too high, the compatibility with polyester is lowered and the effect of promoting crystallization is lost. Further, it is preferable in view of physical properties that the terminal hydroxyl groups are partially etherified, esterified, urethane-modified, and glycidyl ether-modified.

The other monomer having a vinyl group used as the copolymerization component or the trunk polymer component is not particularly limited, but specific examples include styrene, acrylonitrile,
Vinyl acetate, acrylic acid ester, methacrylic acid ester, ethylene, propylene, butylene, acrylic acid,
There are methacrylic acid, glycidyl methacrylate, butadiene, etc., which can be combined with one or more kinds. In particular, styrene, styrene-acrylonitrile, methacrylic acid ester, ethylene, propylene, ethylene-propylene, ethylene-butylene, ethylene-α olefin, and ethylene-propylene-diene are preferable from the viewpoint of compatibility and heat resistance.

Molecular weight 90-500 obtained by employing the above components and method
Polymers having 0 polyether residues and / or aliphatic polyester residues as side chains are polyesters 10
0.5 to 80 parts by weight is blended with 0 parts by weight. 0.
If it is less than 5 parts by weight, the effect is poor, and if it exceeds 80 parts by weight, the properties of the polyester are impaired, which is not preferable. However, a compounding ratio such that the weight fraction of the polyether residue or the aliphatic polyester residue is 1 to 10 parts by weight is particularly preferable. In the above-mentioned polymer, it is desirable that the polyether residue or the aliphatic polyester residue is 10 to 95% by weight, preferably 15 to 90% by weight based on the polymer.

In the present invention, a general nucleating agent such as talc,
It is preferable to blend diatomaceous earth, carbon black, clay, kaolin, mica, silicate, metal oxide, sulfate, phosphate, carboxylate, sulfonate, and ionomer, and among them, talc and carboxylate. , Ionomers are particularly preferred.

In the present invention, a fibrous reinforcing material and / or an inorganic filler may be blended mainly in order to further improve the heat distortion temperature and the dimensional accuracy during heating. As the fibrous reinforcing material that can be used, glass fiber, carbon fiber,
Examples thereof include graphite fiber, nitrogen carbide fiber, whiskers and the like. Particularly, glass fiber and carbon fiber are preferable. Depending on the manufacturing method, various forms such as a chopped strand can be used for roving. Further, it is preferable that these fibrous reinforcing materials have been subjected to a treatment such as a silane treatment, a chromium treatment, an epoxy treatment or the like for the purpose of improving the adhesiveness with a plastic.

Further, as the inorganic filler, talc, wollastonite,
Examples include clay, kaolin, silicates, carbonates and sulfates of Group IIA of the periodic table. Particularly preferred are talc, wollastonite, and carbonates and sulfates of Group IIA of the periodic table. Further, these treatment agents can be used together with an inorganic filler or an inorganic filler which is surface-treated with a silane-based treatment agent, an epoxy resin or the like in order to improve adhesiveness with a resin.

Further, the composition of the present invention may further contain a polyester stabilizer such as an antioxidant and an ultraviolet absorber depending on the use and purpose, as well as a plasticizer, a lubricant, a flame retardant, an antistatic agent, a colorant, and a sliding property. You may mix | blend additives, such as a improver, a foaming agent, and an impact strength improver. As the flame retardant, a compound containing halogen, phosphorus or the like, for example, an organic halogenated compound,
Examples thereof include organic phosphorus compounds. Usually, compounds of Group Vb metal of the periodic table, for example, antimony trioxide are used as a flame retardant aid. A particularly preferred flame retardant is US Pat.
No. 685, JP-A-49-14563, JP-A-52-15346, and the like, carbonates of halogenated bisphenols or oligomers thereof, and JP-A-52-90193. An oligomer obtained by reacting a cyanuric halide with a halogenated bisphenol and optionally a monohydric phenol or a monohydric alcohol as disclosed.

The method for producing the polyester composition of the present invention is not particularly limited and may be any method. For example, a method in which polyester and all other compositions are mixed in advance, and the mixture is supplied to an extrusion base to be melt-mixed, polyester and all compositions other than the fibrous reinforcing agent are mixed, and the mixture is put into an extruder. After charging, the melt is coated around glass roving and cooled, and then cut to an appropriate length by an electric wire coating method, a fibrous reinforcing agent or an inorganic filler is added at the polyester polymerization step or after the polymerization. , A method of mixing all the other compositions with this, and the like. A method of melt-kneading other components into a pellet obtained by kneading and blending any number of components in advance,
Alternatively, the polyester may be divided or melted and kneaded after separate pellets are obtained from any one of the polyesters and other various compounding agents.

〔Example〕

Hereinafter, the present invention will be described with reference to examples. In addition,% and parts in Examples mean% by weight and parts by weight unless otherwise specified.

In addition, various evaluations of molded articles obtained by molding from the compositions in Examples were carried out by the following methods.

1) Releasability, surface characteristics of molded product Judgment was made based on misalignment of mold and sprue when molding a disc having a diameter of 100 mm and a thickness of 3 mm. The surface characteristics were judged by the surface gloss and flow pattern of the disc.

⊚: Very good, ◯: Good, Δ: Quite good, ×: Poor, XX: Very bad.

2) A TC ₁ polyester composition was melted, put into dry ice-methanol, and rapidly cooled to obtain an amorphous sheet, and the amorphous sheet was used in an operating scanning calorimeter (manufactured by Perkin Elmer Co.) in a nitrogen atmosphere at 20
The exothermic peak temperature that appears when the temperature is raised at
_{I set} it to ₁ . It generally represents the crystallization onset temperature.

3) Heat distortion temperature A molded product having a molded product width of 1/16 inch was measured under a load of 18.5 kg / cm ² by ASTM D648.

4) A bleed 1/2 inch x 1/8 inch x 5 inch molded product was placed in a test tube, treated at 150 ° C for 1 week, and then visually observed.

Examples 1 to 6 and Comparative Examples 1 to 5 100 parts of polyethylene terephthalate (hereinafter abbreviated as PET, intrinsic viscosity 0.58, melting point 260 ° C.), 30 parts of polyethylene glycol monomethacrylate whose polyether component has an average molecular weight of 350 and styrene Talc (talcan powder PK, manufactured by Hayashi Kasei Co., Ltd.) and 3 mm long glass chain strand (Glassron chain strand, manufactured by Asahi Fiber Glass Co., Ltd.) are used as a copolymer consisting of 70 parts.
After premixing in the ratio shown in (1), the mixture was put into a hopper of a 40 mmφ2 vent extruder and melt-mixed at a cylinder temperature of 250 to 275 ° C. to obtain a compound chip. The compound chip was dried under reduced pressure at 130 ° C. for 17 hours, and then a test piece was molded by an injection molding machine FS75 (Nissei Plastic Industry Co., Ltd.) controlled at a cylinder temperature of 260-275-275 ° C. and a mold temperature of 70 ° C. The releasability of the obtained molded product, the surface characteristics and the crystallization start temperature of the compound chip were measured,
The results are also shown in Table 1.

As a comparative example, a test piece was prepared in which the resin component was PET alone, a styrene resin not containing polyethylene glycol monomethacrylate, and polyethylene glycol having an average molecular weight of 2000 were prepared, and the evaluation results are shown in Table 1.

As is apparent from Table 1, the polyethylene glycol monomethacrylate / styrene copolymer gives a molded article having excellent mold releasability and surface characteristics.

Example 7 A molding material obtained by compounding in the same manner as in Example 4, except that polyethylene glycol monomethacrylate was changed to polylactone monomethacrylate, had releasability ◎,
The evaluation results are as follows: TC ₁ 92 ° C, heat distortion temperature 218 ° C, and no bleeding. It can be seen that the polylactone monomethacrylate / styrene copolymer also has an excellent effect on low-temperature moldability.

Examples 8-12 The average molecular weight of the polyether residue is 100,200,10.
Table 2 shows the evaluation results of the molding materials obtained by compounding in the same manner as in Example 4 except that polyethylene glycol monomethacrylate consisting of 00,4000 was used.

As is clear from Table 2, the effect is slightly lowered when the average molecular weight of the polyether residue is 5000 or more.

Example 13 Ethylene-α olefin copolymer (Tafuma-P018
0, manufactured by Mitsui Petrochemical Co., Ltd.) 89.5 parts by weight dicumyl peroxide, average molecular weight of polyether residue 350.
Of 10 parts of polyethylene glycol monomethacrylate are mixed, and the twin-screw extruder (P
CM30 manufactured by Ikegai Tekko Co., Ltd.) to obtain a graft copolymer. The molding material obtained by using this instead of the copolymer of Example 5 showed releasability: ◯, TC ₁ 101 ° C., combustion deformation temperature 196 ° C., and no bleeding.

Example 14 A molding material obtained in exactly the same manner as in Example 13 except that low density polyethylene was used in place of the ethylene-α olefin copolymer had releasability: ⊚, TC ₁ 100 ° C., heat distortion temperature 205.
The evaluation result was that there was no bleeding at ℃.

〔The invention's effect〕

The composition of the present invention is excellent in mold releasability and surface characteristics even when molded in a low temperature mold of about 70 to 80 ° C., and has good shape stability at a temperature of the second-order transition point or higher.
Since the bleeding of the improving agent does not occur even at a high temperature of 60 ° C., the field of application thereof is greatly expanded, which greatly contributes to the industrial world.

Claims (3)

[Claims] 1. A polymer obtained from a monomer having a vinyl group in 100 parts by weight of a polyester in which 80 mol% or more of repeating units is ethylene terephthalate is used as a trunk polymer, and a polyether residue and / or a fat having a molecular weight of 90 to 5,000 is used. A polyester composition containing 0.5 to 80 parts by weight of a graft polymer having a group polyester residue as a side chain, wherein the monomer having a vinyl group forming the trunk polymer of the graft polymer is styrene, acrylonitrile, or vinyl acetate. , Acrylic acid ester, methacrylic acid ester, ethylene, propylene,
A polyester composition comprising one or more selected from butylene, acrylic acid, glycidyl methacrylate methacrylate, and butadiene. 2. The polyester composition according to claim 1, further comprising 10 to 150 parts by weight of a fibrous reinforcing material and / or a powdery inorganic filler. 3. The side chain of the graft polymer is obtained from polyalkylene glycol monomethacrylate and / or polylactone monomethacrylate.
The polyester composition according to the item (1).