JPH01272658A - Thermoplastic polyester copolymer composition - Google Patents

Abstract

PURPOSE:To obtain the title composition having excellent releasability and high-cycle molding characteristics especially in a high-temperature mold, by blending a thermoplastic polyester copolymer consisting essentially of a high- melting polyester segment and a low-melting polymer segment with a p- oxybenzoic ester. CONSTITUTION:(A) 100 pts.wt. thermoplastic polyester copolymer consisting essentially of a high-melting polyester segment (e. g., polybutylene terephthalate) having >=150 deg.C melting point and a low-melting polymer segment (e. g., polyoxyethylene glycol) having <=80 deg.C melting point is blended with (B) 0.01-5 pts.wt. p-oxybenzoic ester (e. g., p-oxybenzoic acid 2-ethylhexyl ester).

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a thermoplastic polyester copolymer composition, and more particularly to high-cycle molding of a thermoplastic polyester copolymer.

(Prior Art) Japanese Patent Publication No. 58-58380 has already been published as a method for improving the mold release properties of thermoplastic polyester copolymers using fatty acid metal salts.

(Problem M to be solved by the invention) When a fatty acid metal salt is used as a mold release agent, although it shows good mold release properties in a low-temperature mold, the mold temperature rises in a high-temperature mold or continuous molding. and the mold releasability improvement effect becomes low,
It is not suitable for high-cycle molding, and has the problem that there is a lot of contamination (migration) to the mold surface, and when continuously molded, the surface of the molded product becomes cloudy. Furthermore, when recycled, the mold release effect decreases due to thermal decomposition during polymer melting.

(Means for Solving the Problems) The present invention provides a thermoplastic polyester characterized by blending paraoxybenzoic acid ester with a thermoplastic polyester copolymer mainly consisting of a high melting point polyester segment and a low melting point polymer segment. It is a copolymer composition.

The composition of the present invention has no harmful effect on the polyester copolymer, has mold releasability, and is particularly effective in high-cycle molding using high-temperature molds, and is effective in preventing mold surface contamination and when recycled products are used. Almost no decrease in mold releasability was observed.

The thermoplastic polyester copolymer in the present invention refers to a high melting point polyester segment and a molecular weight of 400 to 6000.
It is a block copolymer consisting of low melting point polymer segments, and when the high polymer is formed only with high melting point polyester segment components, the melting point is 150 ° C or more, and the melting point is measured with only the low melting point polymer segment components. It is a polyester copolymer consisting of constituent components whose melting point or softening point is 80° C. or lower.

Polyesters constituting the high melting point polyester segment include terephthalic acid, isophthalic acid, 1.5-naphthalenedicarboxylic acid, 2.6-naphthalenedicarboxylic acid, 2,
7-naphthalene dicarboxylic acid, bibenzoic acid, bis(P-
(carboxyphenyl)methane, residues of aromatic dicarboxylic acids such as 4,4'-sulfonyl dibenzoic acid, and ethylene glycol, propylene glycol, tetramethylene glycol, pentamethylene glycol, 2,2-dimethyltrimethylene glycol, hexa Polyesters consisting of diol residues such as methylediglycol, decamethylene glycol, P-xylylene glycol, and cyclohexane dimetatool, or copolyesters using two or more dicarboxylic acids or two or more diols, or p- -(β-hydroxyethoxy)benzoic acid, polyesters derived from oxyacids such as p-oxybenzoic acid and their residues, polylactones such as polypivalolactone, 1,2-bis(4,4-dicarboxylic Polyether esters consisting of residues of aromatic ether dicarboxylic acids such as methylphenoxy)ethane and di(4-carboxyphenoxy)ethane and the above-mentioned diol residues, as well as the above-mentioned dicarboxylic acids, oxyacids, diols, etc. Among copolyesters having a melting point of 150° C. or higher, examples may be given of copolyesters in combination with the following. Particularly preferred is polybutylene terephthalate.

The low melting point polymer segment component having a molecular weight of 400 to 6,000 exhibits a substantially amorphous state in the polyester block copolymer, and the melting point or softening point of the segment component alone is 80. ℃ or less, and its molecular weight is suitably from 400 to 6,000. The proportion of the low melting point polymer segment component in the polyester block copolymer is 5 to 80% by weight. Typical low melting point polymer segment components include polyoxyethylene glycol, polyoxypropylene glycol, Examples include polyether glycols such as oxytetramethylene glycol, mixtures thereof, and copolymerized polyether glycols obtained by copolymerizing these polyether components. Further, polyesters consisting of aliphatic or alicyclic dicarboxylic acids having 2 to 12 carbon atoms and aliphatic or alicyclic glycols having 2 to 10 carbon atoms, such as polyethylene adipate, polytetramethylene adipate, polyethylene sebacate, polyneopentyl sebacate, etc. Aliphatic polyesters such as cate, polytetramethylene dodecanate, polytetramethylene azelate, polyhexamethylene azelate, and poly-ε-caprolactone, and two types of aliphatic dicarboxylic acids or two types of glycols. Examples include copolyester. Furthermore, as a component of the low melting point polymer segment, a polyester polyether block copolymer obtained by combining the above-mentioned aliphatic polyester and aliphatic polyether can also be mentioned.

These polyester block copolymers can be produced by conventional polycondensation methods. A preferred method is to conduct an esterification reaction or transesterification by heating an aromatic dicarboxylic acid or its dimethyl ester, a low melting point segment-forming diol, and a low molecular weight diol to about 150 to 260°C in the presence of a catalyst. Then, while removing excess low molecular weight diol under vacuum, Mw! A method for obtaining a polyester block copolymer by carrying out a polymerization reaction, and a method for obtaining a polyester block copolymer by reacting with a pre-prepared high-melting point polyester segment-forming prepolymer and a low-melting point polymer segment-forming prepolymer with a bifunctional polymer that reacts with the end groups of those prepolymers. A method to obtain a polyester copolymer by mixing a chain extender and reacting it, and then keeping the system in a high vacuum to remove volatile components. There are methods for obtaining polyester copolymers by ring-opening polymerization and transesterification. Among these, the thermoplastic polyester copolymer particularly suitable for the present invention is one in which a high melting point polyester segment is copolymerized with polybutylene thiophthalate or 5 to 50 parts by weight of butylene isophthalate per 100 parts by weight of polybutylene terephthalate. The low melting point polymer segment is polytetramethylene glycol. Furthermore, the thermoplastic polyester copolymer used in the present invention is based on the above-mentioned copolymer consisting of a high melting point polyester segment and a low melting point polymer segment, a blend of low molecular or high molecular compounds, a monofunctional component, a polyfunctional component, etc. It also includes chain extension reaction products between copolymers consisting of high melting point polyester segments and low melting point polymer segments, and bonding reaction products with different materials.

As a blend of low molecular weight compounds, 0.01 parts by weight to 10.0 parts by weight of an organic acid metal salt compound may be blended with 100 parts by weight of the base thermoplastic polyester copolymer. Examples of blends of polymer compounds include polyolefins, polystyrenes such as acrylic-butadiene-styrene and acrylic-ethylene-styrene, and polyvinyl chloride in addition to polyesters such as polybutylene terephthalate and bolyene phthalate. Can be mentioned.

Furthermore, examples of producing products by reaction include chain extension reactions between base polymers and thermoplastic polyester copolymers with the same or different ratios of high melting point polyester segments and low melting point copolymer segments; A polyfunctional component having two or more functionalities and a polyvalent epoxy compound, a polyvalent isocyanate compound, and a polyvalent oxazoline compound are used in the bonding reaction of different materials. However, at the same time, two or more of the same or different types of polyfunctional components may be combined, and monofunctional components may be used in combination for terminal blocking.

In particular, to increase the melt viscosity of thermoplastic polyester copolymers, compounding dimer acid sodium salt, compounding ionomer which is a copolymer of ethylene and metal carboxylate, and chain extension using polyfunctional epoxy compounds and polyfunctional isocyanate compounds. Useful as a means of reaction. Grades with such thickening formulations generally have slow solidification and are sticky, 1 and often have poor release properties from molds during injection molding. Even in such cases, roseoxybenzoic acid ester is effective as a mold release agent, and there is no deformation of the molded product due to the ejection bottle, and high-cycle processing is possible.

The roseoxybenzoic acid ester used in the present invention is represented by the general formula H, (wherein R is composed of an alkyl group, an aromatic group, or an alicyclic group).For example, roseoxybenzoic acid butyl ester, roseoxybenzoic acid cyclohexyl ester, Examples include roseoxybenzoic acid-2-ethylexyl ester. In particular, roseoxybenzoic acid-2-ethylexyl ester is preferred.Here, when the amount of roseoxybenzoic acid ester blended is 0.01 part by weight or less per 100 parts by weight of the thermoplastic polyester copolymer, the release property is improved. It does not show 5.
If it exceeds 0 parts by weight, the elastic modulus decreases due to the plasticizing effect, which changes the properties of the resin before blending, which is not preferable.

The present invention involves the polymerization of thermoplastic polyester copolymers, blending of low-molecular compounds and high-molecular compounds, chain extension reactions, bonding reactions with different materials, compounds in which stabilizers and colorants are kneaded, and tri-blending during molding. Although the rose oxybenzoate ester can be blended at any stage, stabilizers, colorants, and in some cases, low-molecular compounds, high-molecular compounds, and polyfunctional compounds are added to the thermoplastic polyester copolymer and the rose oxybenzoate ester during compounding. The components are simultaneously blended in a tumbler, melt-mixed in a single-screw or twin-screw extruder at a temperature generally in the range of 180 to 250°C, and then chips are obtained through a series of steps of cooling, solidification, and granulation. Are suitable.

Methods of granulation include extruding it into a sheet and turning it into chips using a dicer, extruding the strands into the air and immediately turning them into chips with a pelletizer after cooling them in water, and immediately turning them into chips using an underwater cutter or hot cut. be.

Although the composition of the present invention has many desired properties, the above properties can be significantly stabilized very easily by further incorporating a stabilizer against ultraviolet rays, a stabilizer against thermal oxidation, and a stabilizer against hydrolysis. Typical stabilizers useful as stabilizers include substituted benzophenones or substituted benzotriazoles as stabilizers against ultraviolet radiation, and phenol derivatives such as tetrakis[methylene-3(3,5-
di-tert-butyl-41-hydroxyphenyl)propione-1-)methane, 1,3.5-trimethyl-2,
4,6-1-lith[3,5-ditertiary-butyl-4
-Hydroxybenzyl]benzene, 4,4'-thiobis(3-methyl-6-tert-butylphenol), 4
．． Aromatic amines such as 4'-butylidene bis(6-tert-butylmetacresol), e.g. 4.4'-
(α,α-dimethylbenzyl)diphenylamine, N,
N'-diphenyl-p"-phenylenediamine, N,
N'-bis(β-naphthyl)-paraphenylenediamine, N,N'-bis(l-methylhebutyl)-paraphenylenediamine, etc., thiodipropionic acid esters, such as dilauryldithiopropione-1, di- Examples include stearyl dithiopropionate. Combinations of these are also useful. Stabilizers against hydrolysis include carbodiimides and the like.

The composition of the present invention may include antistatic agents, plasticizers,
Inorganic and organic powder fillers, organic and inorganic fibrous fillers,
H fuel, organic and inorganic pigments, fluorescent brighteners, etc. can also be blended. These blends can be carried out at any stage from polymerization to compounding.

Production Examples 1 to 3 The polymers used in Examples and Comparative Examples are as follows.

Polymer C: Using dimethyl terephthalate, 1,4-butanediol, and polyoxytetramethylene glycol (PTNG) with a number average molecular weight of about 1000, PT
A polyester/polyether block copolymer was produced in which lIG units accounted for 25%.

Melt index was 22 g/Rosin.

Polymer B: A polyester-polyester block copolymer was produced by heating and mixing 100 parts by weight of polybutylene terephthalate and 50 parts by weight of ε-caprolactone, and carrying out a transesterification reaction while ring-opening polymerizing the lactone. Melt index was 40 g/10 claims.

Polymer C: Dimethyl terephthalate and dimethyl isophthalate were mixed in a ratio of 3=1, and 1.4-butanediol and polyoxytetramethylene glycol (PTMG) having a number average molecular weight of about 1000 were used to form PT.
A polyester/polyether block copolymer in which NG units account for 25% had a melt index of 26 g/Login.

Various properties of the polymers of Production Examples A to C are shown in Table 1.

(Example) Hereinafter, the present invention will be explained with reference to Examples. In the examples, parts simply indicate parts by weight.

Melt index, JIS 117210 test / Temperature 230°C / Load 2160 g Ejection resistance A pressure sensor is attached after the ejection bottle in the middle of the crab core nest, and after the resin flowing from the sprue solidifies into a cylindrical shape with a direct gate, the mold The pressure applied to the ejector was measured when the molded product was removed from the core nest using the ejector.

Reflectance: Tokyo Denshoku Co., Ltd. gloss meter, model T
Using C-i0811, the reflectance of the surface after continuously molding a molding plate with Loom sides 100 times... (Reflected light W/1 t of incident light) xxoo% (Incidence angle 45°, Reflection angle 4
5°) was expressed as the retention rate for the reflectance of the initially molded plate.

Undercut ratio: A molded product having an undercut portion of 18Φ×15h and a wall thickness of 2t was ejected from a plate, and the undercut ratio was determined from the ejectable ratio.

Examples 1-3 10ob each of polymers A, B, and C shown in Production Examples 1-3
0.1k of paraoxybenzoic acid butyl ester
g and other stabilizers, melted and mixed in a single-screw extruder, discharged, solidified into a strand shape in a water tank, and then chipped. This chip was used for molding after drying.

Examples 4 to 6 To 100 kg each of polymers A, B, and C, 1 kg of paraoxybenzoic acid-2-ethylexyl ester was added together with other stabilizers, melted and mixed in a single screw extruder, and solidified into a strand shape in a water tank after discharge. After that, it was made into chips. This chip was used for molding after drying.

Example 7 To 100 kg of Polymer A, 2 kg of roseoxybenzoic acid butyl ester and diphenylmethane diisocyanate were added together with ZCG and other stabilizers, melted and mixed in a single-screw extruder, discharged, solidified into a strand shape in a water tank, and then made into chips. It became. This chip was used for molding after drying. The melt index was 3 g/10w1n.

Comparative Examples 1 to 3 To each of polymers A, B, and C, 5 g of roseoxybenzoic acid-2-ethylexyl ester was added and melt-mixed using a single-screw extruder, solidified into a strand shape in a water tank, and then chipped. . This chip was used for molding after drying.

Comparative Examples 4 to 6 To 100 kg each of Polymers A, B and C, 0.2' of calcium montanate salt was added and melt-mixed in a single-screw extruder, solidified into strands in a water bath, and then chipped. This chip was used for molding after drying.

The following margin recycling test: Next, Manufacturing Examples A, B, C1 Examples 4 to G and Comparative Example 4
After crushing the molded products of ~6 and the sprue runner during molding using a plastic crusher (manufactured by Horai Tekkosho, model MD4CZ), the powder was removed, and the weight ratio was 50:5.
The mixture was mixed with virgin chips at 0 and dried, and then used for molding. This recycling process was repeated three times. Table 3 shows the ejection resistance of virgin products and three-times recycled products.

Margins below (Effects of the Invention) The thermoplastic polyester copolymer composition of the present invention has excellent 71-cycle moldability, especially in high-temperature molds, and does not mold as easily as conventional mold release agents even during continuous molding. It is extremely useful industrially because it does not cause contamination (migration) to the mold surface, does not impair the appearance of the molded product, and can maintain these characteristics even when recycled.

Patent applicant: Toyobo Co., Ltd.

Claims (1)

[Scope of Claims] A thermoplastic polyester copolymer composition characterized by blending paraoxybenzoic acid ester with a thermoplastic polyester copolymer mainly consisting of a high melting point polyester segment and a low melting point polymer segment.