JPH0220551A - Injection-moldable polyester resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition which can give a molding excellent in mechanical strengths, heat resistance and surface smoothness even at low mold temperature by mixing a mixture of a polyethylene terephthalate resin with a specified block copolymer with a glass fiber, a specified wollastonite and talc. CONSTITUTION:100pts.wt. mixture (A) comprising 20-90pts.wt. polyethylene terephthalate resin and 10-80pts.wt. block copolymer comprising 10-45wt.% polyether compound and 55-90wt.% polyethylene terephthalate resin and/or ethylene terephthalate resin oligomer is mixed with 10-35pts.wt. glass fiber (B), 4-11pts.wt. wollastonite (C) surface-treated with an aminosilane compound and/or an epoxysilane compound and 1-5pts.wt. talc (D). In this way, the title composition which can give a molding excellent in surface properties, mechanical strengths and heat resistance even at a mold temperature <=100 deg.C can be obtained.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a polyester resin composition for injection molding that provides a molded article with excellent surface properties, mechanical strength, and heat resistance even at a mold temperature of 100°C or less. relating to things.

[Prior Art/Problems to be Solved by the Invention] Glass fiber reinforced polyethylene terephthalate resin is widely used as a molding material because of its excellent mechanical strength and heat resistance.

However, since polyethylene terephthalate resin has a slow crystallization rate, the mold temperature during injection molding is 1.
It requires a temperature of 40°C or higher, which is disadvantageous in terms of processing.

On the other hand, in order to increase mechanical strength and heat resistance, it is essential to fill the molded product with glass fibers, but as a result, the glass fibers appear on the surface of the molded product and flow patterns can be seen, which poses significant limitations in terms of use. ing.

As a method for improving such drawbacks, methods using various crystallization promoters have been known. For example, Japanese Patent Publication No. 48-4097 proposes a method of adding an organic acid metal salt, and Japanese Patent Publication No. 55-47059 proposes a method of adding a plasticizer and an ionomer. In these methods, the mold temperature during injection molding is 100℃.
In the following, the glossiness of the surface of the molded product can be increased (improved gloss), but at the same time the mechanical strength is greatly reduced. Moreover, the smoothness of the glossy surface is low, making it unsuitable for use in exterior parts.

On the other hand, JP-A-50-90649 describes a method of adding three components, glass fiber, wollastonite and talc, to saturated polyester. However, with this method, it has not been possible to obtain a material with a large filling amount and a surface property suitable for use in exterior parts.

Thus, there is a strong demand for a composition that can be injection molded even at a mold temperature of 100°C or less, has high gloss, is highly smooth, and provides molded products with excellent mechanical strength and heat resistance. has been done.

[Means for Solving the Problems] In view of the above-mentioned circumstances, the present invention provides an injection method that provides molded products with high glossy surface smoothness and excellent mechanical strength and heat resistance even at mold temperatures of 100° C. or lower. It was made to obtain a polyester resin composition for molding, and contains 20 to 90 parts (by weight, the same applies hereinafter) of a polyethylene terephthalate resin and 10 to 4 parts of a polyether compound.
100 parts of a mixture consisting of 10 to 80 parts of a block copolymer consisting of 5% (by weight, the same applies hereafter) and 55 to 90% of a polyethylene terephthalate resin and/or an ethylene terephthalate resin oligomer; B) 10 to 80 parts of glass fiber; 35 parts, (C) Wollastonite surface-treated with an aminosilane compound and/or an epoxysilane compound 4-1.
and (D) 1 to 5 parts of talc.

[Example] The polyethylene terephthalate resin referred to herein refers to one containing at least 90 mol% of terephthalic acid or its ester-forming derivative as an acid component, and ethylene glycol or its ester as a glycol component. It refers to a polyethylene terephthalate resin obtained using a derivative containing at least 90 mol % of a derivative having the ability to form a polyethylene terephthalate.

Acid components other than terephthalic acid and its derivatives having ester forming ability used in the range of less than 10 mol% include other aromatic dicarboxylic acids having 8 to 17 carbon atoms, aliphatic dicarboxylic acids having 4 to 10 carbon atoms; , and even carbon number 8-1
Specific examples thereof include phthalic acid, isophthalic acid, and 2.2 alicyclic dicarboxylic acids. Examples include B-naphthalenedicarboxylic acid, 4.4°-diphenyldicarboxylic acid, adipic acid, sepacic acid, and cyclohexanedicarboxylic acid.

In addition, diol components other than ethylene glycol and its derivatives having ester-forming ability used in the range of less than 10 mol% include aliphatic diols having 3 to 10 carbon atoms, alicyclic diols having 6 to 15 carbon atoms, Further examples include aromatic diols having 6 to 15 carbon atoms, such as propane-1,3-diol, butane-1,4-diol, pentane-1,5-diol,
Hexane-1,8-diol, cyclohexane-1,4
-dimethator, 2,2-dimethylpropane-1,3-
Examples include diol, 2.2-bis(4°-hydroxycyclohexyl)propane, 2.2-bis(4°-hydroxyphenyl)propane, and hydroquinone.

Polyethylene terephthalate resin produced from the above components usually has an intrinsic viscosity of 0.35 to 1.20 (
Phenol/1.1.2.2-Tetrachloroethane-
50750 (ffi amount ratio), 0.5% concentration, 25°C 1.
The same applies hereinafter), but from the viewpoint of achieving a good balance between crystallization rate and mechanical strength, those with an intrinsic viscosity of 0.40-0.70 are preferable, and 0.45-0.
．． 65 is more preferable.

In the present invention, 10 to 45% of polyether compound,
Preferably 55 to 90% of an ethylene terephthalate resin oligomer containing, as a typical example, an ethylene terephthalate oligomer manufactured from the same raw materials as those constituting the polyethylene terephthalate resin and/or the polyethylene terephthalate resin. A block copolymer is produced from 65 to 85%.

In addition, the ethylene terephthalate oligomer or ethylene terephthalate resin oligomer referred to in this specification refers to an ethylene terephthalate oligomer or alkylene terephthalate resin oligomer having a plurality of ethylene terephthalate units or a plurality of alkylene (ethylene units are 90 mol% or more) terephthalate units. The concept includes not only ethylene terephthalate units, Gt alkylene terephthalate units, but also only terephthalate units that are sometimes included.

The polyether compound referred to in this specification has the general formula (I) NI〇→RIO)T (1) (wherein, R1 is a divalent group having 2 to 18 carbon atoms, 2 is an integer of 5 to 40, It is a compound having a main portion (the portion excluding the terminal) represented by the following formula (the g R1s do not necessarily have to be the same).

Specific examples of R1 include ethylene, propylene, isopropylene, butylene, bisphenol A residue, etc. Among polyether compounds having the main part represented by general formula (1), polyethylene glycol, polypropylene glycol, Polytetramethylene glycol, etc., general formula (■): (wherein, R2 is a divalent hydrocarbon group X of 02 to C4, for example, -C(C)Is)2- -CH2- -8-
Compounds having a main moiety represented by a divalent bonding group such as -8O2--CO- or a direct bond, m and n each an integer of 5 to 20, and R2 in (m+n) do not need to be the same), etc. and has an average molecular weight of 700 to 200
0 is preferable from the viewpoint of increasing the crystallization rate of the resulting composition and improving injection moldability.

If the content of the polyether compound in the block copolymer is less than 10%, the gloss cannot be increased at a mold temperature of 100°C or less, and if it exceeds 45%, the mechanical strength and heat resistance of the molded product will deteriorate. decreases, both of which are unfavorable.

The block copolymer produced in this way is usually 0
．． It has an intrinsic viscosity of 35 to 1.20, but from the viewpoint of improving the crystallization rate and mechanical strength in a well-balanced manner, an intrinsic viscosity of 0.40 to 1.00 is preferable, and 0.40 to 1.00 is preferable. More preferably, it is 50 to 0.80.

The block copolymer may be manufactured by copolymerizing in a polyester synthesis reaction vessel or by copolymerizing in an extruder.

In the present invention, 20 to 90 parts of the polyethylene terephthalate resin, preferably 40 to 85 parts, more preferably 50 to 80 parts, and 10 to 80 parts of the block copolymer,
Preferably 15 to 60 parts, more preferably 20 to 50 parts
The content of units derived from the polyether compound is preferably 5 to 25%, more preferably 7 to 20%.
%, particularly preferably 7 to 15% (component (A))
100 parts are prepared.

If the proportion of the block copolymer exceeds 80 parts, the mechanical strength and heat resistance will decrease, and if the proportion is less than 10 parts, the effect of using the block copolymer will not be sufficiently obtained. Furthermore, if the content of units derived from polyether compounds is less than 5%, it tends to be difficult to increase the gloss at mold temperatures of 100°C or less, and if it exceeds 25%, the mechanical strength
There is a tendency for heat resistance to decrease.

There is no particular limitation on the method for preparing the prisoner component, and it may be prepared by mixing only the above-mentioned components, or other components may be added and mixed all at once.

The glass fiber (component (B)) used in the present invention preferably has a diameter of 1 to 20 m and a length of about 0.05 to 50 m5, and may be treated with a coupling agent or treated with a binder. It may be something. Preferred examples of the coupling agent include alkoxysilane compounds such as γ-aminopropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane, and preferred examples of the binder include epoxy resins and urethane resins. However, it is not limited to these.

The amount of glass fiber used is 1 per 100 parts of the prisoner component.
It is 0 to 35 parts, preferably 12 to 30 parts.

If the amount used is less than 10 parts, the mechanical strength will decrease and 3
If the amount exceeds 5 parts, the smoothness of the glossy surface cannot be changed.

Wollastonite (component (C)) used in the present invention is C
It is a crystalline calcium metasilicate whose main component is aSiO3, and whose surface has been treated with an aminosilane compound and/or an epoxysilane compound. Not only when the surface is not treated, but also when other coupling agents such as titanate compounds, vinyl silane compounds, meltcaptosilane compounds, etc. are used, it is difficult to uniformly disperse them in the composition. Not only is it impossible to improve the smoothness of the glossy surface, but also the mechanical strength and heat resistance are reduced.

Although there is no particular limitation on the particle size of the wollastonite, those having an aspect ratio of about 5 to 30 are preferable from the viewpoints of surface properties, mechanical strength, and heat resistance.

Examples of the aminosilane compound include γ-
Aminoprobilt ethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethobovdisilane, γ-(polyethyleneamino)propyltrimethoxysilane, N-β-(aminoethyl)-γ- Examples include aminopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane is particularly preferred in terms of surface properties, mechanical strength, and heat resistance.

Further, examples of the epoxysilane compounds include β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, etc. In particular, γ-glycidoxypropyltrimethoxysilane is preferred in terms of surface properties, mechanical strength, and heat resistance.

These compounds are added to 100 parts of wollastonite,
Usually about 0.3 to 1.5 parts are added and the surface can be treated by tri-blending or the like.

The amount of these surface-treated wollastonites used is (5)
4 to 11 parts, preferably 5 to 10 parts per 100 parts of ingredients
Department. If the amount used is less than 4 parts, the smoothness of the glossy surface cannot be improved, and if it exceeds 11 parts, the mechanical strength will decrease.

Talc (component (D)) used in the present invention has a composition formula: Mg
The main component is a compound represented by s SiOx 010 (011)2, and preferably has an average particle size of 3 μm or less. If the average particle size exceeds 3 μ, the dispersibility in the composition tends to deteriorate, it becomes difficult to improve the smoothness of the glossy surface, and the mechanical strength and heat resistance tend to decrease.

The amount of talc used is 1 to 5 parts, preferably 2 to 4 parts, based on 100 parts of the prison component. If the amount is less than 1 part, the smoothness of the glossy surface will not be sufficiently improved, and if it exceeds 5 parts, the mechanical strength will decrease.

In order to further increase crystallinity, the composition of the present invention contains sodium acetate, sodium benzoate, sodium phthalate, disodium phthalate, magnesium stearate, sodium stearate, calcium stearate, sodium palmitate. , sodium montanate, sodium pt-butylbenzoate, and other organic acid salts; sodium carbonate, calcium carbonate, calcium silicate, magnesium silicate, calcium sulfate, barium sulfate, and other organic salts; zinc oxide,゛Metal oxides such as magnesium oxide and titanium oxide; so-called ionomers such as metal salts of ethylene-acrylic acid copolymers; structures in which one end of polyalkylene glycol is an organic gold salt. It may also contain compounds such as.

The resin composition of the present invention may contain additives commonly used in molding resin compositions, such as stabilizers, colorants, antistatic agents, flame retardants, processability improvers, and the like.

The resin composition of the present invention can be produced by various known methods, such as a method using an extruder.

The composition obtained in this way (for example, pellets) can be injection molded well even at a mold temperature of 100°C or less, and the obtained molded product has excellent surface properties, mechanical strength, and heat resistance. has.

Note that it is preferable to dry the resin, additives, and pellets to a very low moisture content (generally 0.02% or less) before injection molding.

The present invention will be described in detail below with reference to Examples, but the present invention is not limited to these Examples.

In addition, the tensile strength of the molded products in Examples and Comparative Examples was determined according to ASTM-D638, and the heat resistance was determined according to the heat distortion temperature (HDT).
) (18,8kg/c-load) to ASTM-08
Evaluation was made in accordance with 48. The smoothness of the glossy surface of the molded product is 8
The glossiness and surface roughness (Rax) of the plate surface of 0 m5 x 50 I x 1 m x 21 I were evaluated. Gloss level is J
Based on ISK-7105, 80% or more is in a good range, Riax is based on JIS B-0801, and 3.
A good range is Dμ or less.

Examples 1 to 3 30% of an ethylene oxide addition polymer of bisphenol A with an average molecular ffi of 1000 and 70% of ethylene terephthalate oligomer (average degree of polymerization n-7) were melt-kneaded under reduced pressure to form an ethylene oxide addition polymer of bisphenol A. A copolymerized copolymer (hereinafter also referred to as copolymer (1)) having an intrinsic viscosity of 0.80 was obtained. This copolymer and polyethylene terephthalate having a viscosity of o and eo were dried to a moisture content of 0.01% or less, blended in the proportions shown in Table 1, and further tetrakis[methylene-3 (3°, 5° −
0.2 part of di-t-butyl-4°-hydroxyphenyl)propionate comethane, tris(2,4-di-t-
butylphenyl) phosphite (0.2 parts), pentaerythritol tetrakis(β-laurylthiopropionate) (0.2 parts), sodium pt-butylbenzoate (0.5 parts), and wollastonite (100 parts). γ
- Wollastonite having an aspect ratio of 20 and having been surface-treated using 0.5 parts of glycidoxypropyltrimethoxysilane and talc having an average particle size of 1.8 were added and mixed in the proportions shown in Table 1. Next, the twin screw extruder PCM manufactured by Ikegai Iron Works ■
-45 was used to melt-knead the mixture, and glass fibers (diameter 9 mm, length 3 am) were added in the amount shown in Table 1 from the middle of the twin-screw extruder to obtain a pelletized resin composition. Extrusion temperature conditions are 280℃ to 270℃ from the hopper side to the die side.
A temperature gradient of For other conditions, general conditions were selected to ensure stable extrusion.

The pelletized resin composition obtained was dried to a moisture content of 0.02% or less, and an injection molding machine (manufactured by Toshiba Machine ■, 18-75B) was used.
) at a mold temperature of 90'C, and the performance was evaluated. The results are shown in Table 1.

In either case, mechanical strength and heat resistance are good,
The surface had excellent gloss and smoothness.

Comparative Example 1 Evaluation was carried out in the same manner as in Example 1 except that wollastonite and talc used in Example 1 were not used. The results are shown in Table 1. Although the surface gloss was good, the smoothness was poor.

Comparative Examples 2 to 5 The wollastonite and talc used in Example 1 were
Evaluation was carried out in the same manner as in Example 1 except that the parts shown in the table were used.

The results are shown in Table 1.

In all cases, excellent mechanical strength, heat resistance, surface gloss and smoothness were not achieved.

Comparative Examples 6 to 7 Instead of the wollastonite used in Example 1, wollastonite surface-treated with 0.5 parts of isopropyl or triisostearoyl titanate per 100 parts of wollastonite was used (Comparative Examples) 6) Evaluation was carried out in the same manner as in Example 1, except that wollastonite surface-treated with 0.5 part of mercaptopropyltrimethoxysilane was used (Comparative Example 7). The results are shown in Table 1.

All were inferior in mechanical strength and surface smoothness.

Comparative Examples 8 to 9 95 parts of polyethylene terephthalate and 5 parts of copolymer (1) used in Example 1 (Comparative Example 8), 10 parts of polyethylene terephthalate, and 5 parts of copolymer (1)
Evaluation was carried out in the same manner as in Example 1, except that 90 parts of 1) was used (Comparative Example 9). The results are shown in Table 1.

In the case of Comparative Example 8, the gloss was low and the smoothness was also greatly inferior. In addition, in the case of Comparative Example 9, mechanical strength,
It had poor heat resistance.

Examples 4 to 5 In place of the copolymer (1) used in Examples 1 to 3, polypropylene glycol (E
O/PO-20/80 (ffi amount ratio)) 35% and ethylene terephthalate oligomer (average degree of polymerization 8) 65%
A copolymer (hereinafter referred to as copolymer (2)) with an intrinsic viscosity of 0.65 obtained by melt-kneading and copolymerizing polypropylene-based glycol under reduced pressure was used as the wullast used in Examples 1 to 3. Evaluation was performed in the same manner as in Example 1 using wollastonite surface-treated with 0.5 parts of γ-aminopropyltriethoxysilane per 100 parts of wollastonite instead of night.The results are shown in Table 1. .

All had good mechanical strength and heat resistance, as well as excellent surface gloss and smoothness.

Example 6 In place of the copolymer (1) used in Examples 1 to 3, a solid consisting of 15% ethylene oxide addition polymer of bisphenol A with an average molecular weight W too and 85% ethylene terephthalate oligomer (average degree of polymerization 7) was used. A copolymer having a viscosity of 0.73 (hereinafter referred to as copolymer (3)) was used and evaluated in the same manner as in Examples 1 to 3. The results are shown in Table 1.

It had good mechanical strength and heat resistance, as well as excellent surface gloss and smoothness.

Example 7 In place of the copolymer (1) used in Examples 1 to 3, a unique polymer consisting of 20% ethylene oxide addition polymer of bisphenol A with an average molecular m 1000 and 80% ethylene terephthalate oligomer (average degree of polymerization 7) was used. Evaluations were made in the same manner as in Examples 1 to 3 using a copolymer with a viscosity of 0.78 (hereinafter referred to as copolymer (4)). The results are shown in Table 1.

It had good mechanical strength and heat resistance, as well as excellent surface gloss and smoothness.

[Effects of the Invention] When the composition of the present invention is used, molded products with excellent mechanical strength, heat resistance, and surface smoothness can be obtained even at mold temperatures of 100° C. or lower.

Special permission Out wish Man Kanebuchi Chemical Industry Co., Ltd.

Claims (1)

[Claims] 1 (A) Polyethylene terephthalate resin 20-9
0 parts by weight and 10-45% by weight of polyether compound
and polyethylene terephthalate resin and/or
100 parts by weight of a mixture consisting of 10 to 80 parts by weight of a block copolymer consisting of 55 to 90 parts by weight of ethylene terephthalate resin oligomer, (B) 10 to 35 parts by weight of glass fiber, (C) an aminosilane compound and/or epoxy Wollastonite 4-11 surface treated with silane compound
A polyester resin composition for injection molding, comprising parts by weight and (D) 1 to 5 parts by weight of talc.