JPS6357665A - Polyester resin composition - Google Patents

Abstract

PURPOSE:To provide the title compsn. having excellent molding stability, flow characteristics and moldability and a high crystallization velocity, by blending a satd. polyester resin with a specified low-molecular terpolymer (salt). CONSTITUTION:A copolymer of a relatively high-molecular ethylene (a) with an alkyl ester of an alpha,beta-unsaturated carboxylic acid (b) is thermally degraded in an inert atmosphere in the presence of water at 200-500 deg.C under a pressure of 5-500kg/cm<2> for 1-10hr to obtain a low-molecular terpolymer (B) having an ethylene content of 80-99.5mol%, a content of a mixture (of an alpha,beta-unsaturated carboxylic acid and an alkyl ester of an alpha,beta-unsaturated carboxylic acid in a ratio of 10-90% to 90-10%) of 0.5-20mol% and an intrinsic viscosity (in decalin at 135 deg.C) of 0.07-0.6. 100pts.wt. satd. polyester resin (A) is blended with 0.2-30pts.wt. component B and/or salt thereof obtd. by reacting part of the whole of the carboxyl groups of the component B with a mono- to trivalent metallic compd. and optionally, 10-150pts.wt. filler (C).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a polyester resin composition with excellent molding stability.

[Prior Art] Polyester resins are used in a wide range of fields as various molded products by taking advantage of their excellent properties.

However, when these polyester resins are molded at a temperature of 250° C. or higher, the molecular weight partially decreases due to thermal decomposition, and the melt viscosity decreases over time.

In particular, in injection molding, etc., where the resin is kept at a high temperature for a relatively long time, the melt viscosity decreases significantly, causing problems in molding stability.

Regarding the improvement of such drawbacks, for example, Japanese Patent Application Laid-open No. 1986-
Publication No. 83047 proposes a composition J consisting of a saturated polyester resin and an ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid ester-unsaturated carboxylic acid metal salt copolymer having a certain range of composition. It is disclosed that when processed into a molded article, the stability of the melt viscosity is good, so the moldability is good.

However, as is clear from the examples, the copolymer proposed in the publication is a metal chloride of a copolymer produced using ordinary high-pressure polyethylene production equipment, and its average molecular weight is relatively high. Become something.

However, when such a copolymer having a relatively high average molecular weight is blended with a polyester resin, it is difficult to be sufficiently uniformly dispersed in the polyester resin, and the fluidity of the composition is reduced. Furthermore, the stability of the melt viscosity of the composition is still not sufficient.

On the other hand, JP-A No. 60-35049 states that ``A polyester resin is blended with an α-olefin having an average molecular weight of less than ff1s, ooo and an α,β-unsaturated carboxylic acid copolymer in which a portion of the copolymer is a metal salt. A "composition" has been proposed, which can be easily kneaded sufficiently uniformly with polyester in a molten state,
Moreover, it is disclosed that moldability is good because the melt after cross-crossing has good fluidity.

However, in experiments conducted by the present inventors, no improvement in the melt viscosity stability of polyester at high temperatures was observed even when the metal salt of the above-mentioned copolymer was blended into polyester.

[Problems to be Solved by the Invention] An object of the present invention is to prevent a decrease in the melt viscosity of a polyester resin at high temperatures, maintain molding stability, and at the same time improve the fluidity of the composition and copolymerize with the polyester resin. It is an object of the present invention to provide a polyester resin composition that exhibits good homogeneity with coalescence and/or copolymer salts, and further with fillers.

[Means for solving the problems] The present invention provides at least saturated polyester resin (A) 1
In the 001ffi part, ethylene of relatively high molecular weight m and α, β
- Ethylene 80 to 99.5 mol%, α, obtained by thermal degradation of a copolymer with an unsaturated carboxylic acid alkyl ester
, β-unsaturated carboxylic acid and α.

The total content of β-unsaturated carboxylic acid alkyl ester is 0.5 to 20 mol%, the composition ratio of the acid and alkyl ester is 10 to 90% to 90 to 10%, and 13
A low molecular terpolymer (B) having an intrinsic viscosity in the range of 0.07 to 0.6 in decalin at 5°C and/or at least one carboxylic acid unit of the terpolymer (B)
A copolymer salt (B)' formed by reacting part or all of the atoms with a compound of a metal selected from monovalent to trivalent metals.
This is a polyester resin composition containing 0.2 to 30 parts by weight.

As the saturated polyester (A) of the present invention, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycyclohexane 1,4-dimethylol terephthalate and copolymers thereof are suitable. As the acid component, it is also possible to use terephthalic acid together with one or more of other aromatic or aliphatic dicarboxylic acids, such as isophthalic acid, phthalic acid, adipic acid, azelaic acid, and sebacic acid, depending on the purpose. .

Furthermore, the glycol components include ethylene glycol, 1
．． Besides 4-butanediol, the use of modified saturated polyesters containing other aliphatic diol components, such as neopentyl glycol, polytetramethylene glycol, etc., may also be used.

Among these, preferred polyesters in the present invention are:
Polyethylene terephthalate, polybutylene terephthalate, and a copolyester having at least 80 mol % of ethylene terephthalate as a repeating unit, particularly preferably polyethylene terephthalate.

The polyester used in the present invention preferably has an intrinsic viscosity of 0.4 or more from the viewpoint of the strength of the molded product. The intrinsic viscosity here is 30°C in a 1:1 weight ratio of phenol/tetrachloroethane mixture m*.
This is the value measured at

Ethylene which is component (B) and (B)' of the present invention
α.

β-unsaturated carboxylic acid-unsaturated carboxylic acid alkyl ester copolymer or its metal salt is produced by thermally decomposing commercially available ethylene-α,β-unsaturated carboxylic acid ester with relatively high molecular weight. At least a part or all of the heat-degraded product or the heat-degraded product has a valence of 1 to 31i11
It is reacted with a compound of metal i.

For example, an ethylene-(meth)alkyl acrylate copolymer is prepared as a relatively high molecular weight ethylene-α,β-unsaturated carboxylic acid alkyl ester in the presence of water in an inert atmosphere at a temperature of 81°C at 200-500°C under a pressure of 5°C. ~500Kg/cs
Ethylene-(meth) by reacting under the conditions of
An acrylic acid-alkyl (meth)acrylate copolymer can be produced.

The relatively high-molecular ethylene-α,β-unsaturated carboxylic acid alkyl ester copolymer used in the present invention before degradation is preferably an ethylene and acrylic acid or methacrylic acid alkyl ester copolymer, known in the art. It can be easily obtained by high-pressure copolymerization method. The above copolymer has a melt index of about 30 G9/1 G min or less, and an unsaturated alkyl carboxylate content m in the molecular chain of about 0.5 to 25 mol%, preferably 1 to 15 mol%.

Specific examples of the ethylene-α,β-unsaturated carboxylic acid alkyl ester copolymers include ethylene-ethyl acrylate, ethylene-methyl methacrylate, ethylene-acrylic In-propyl, ethylene-isopropyl acrylate, and ethylene-acrylic acid. A copolymer of ln-butyl, ethylene-5ec-butyl acrylate, t13rt-butyl acrylate, etc., and the alkyl of the unsaturated carboxylic acid alkyl ester is an alkyl group having 1 to 4 carbon atoms, that is, a methyl group, an ethyl group. group, isopropyl group, n-
Butyl group, isobutyl group, tert-butyl group, etc. are preferred.

The method of thermally degrading the above ethylene-α,β-unsaturated carboxylic acid alkyl ester copolymer includes ethylene-α,β-
It is controlled by factors such as the average molecular weight of the unsaturated carboxylic acid alkyl ester copolymer, the content of α,β-unsaturated carboxylic acid alkyl ester, the degree of low molecular weight 8 conversion, and the amount of coexisting water. A repulsion section [200-500℃, reaction pressure 5-500Kg/
ci, reaction time is 1 to 10 hours, preferably 2 to 6 hours.

In addition, the above thermal degradation method has already been used in the
This is detailed in the 9008 publication and the like.

Ethylene-α of the present invention thus obtained.

β-unsaturated carboxylic acid-α, β-unsaturated carboxylic acid alkyl ester copolymer (B) is ethylene 80-99
．． 5 mol%, α, β-unsaturated carboxylic acid and α, β-
The total content m of unsaturated carboxylic acid alkyl esters is 0.
5 to 20 mol%, preferably 1 to 10 mol%, the composition ratio of the acid and ester is 10 to 90% to 90 to 10%, and the intrinsic viscosity in decalin at 135 ° C. is 0.0
It is a terpolymer with a low molecular value in the range of 7 to 0.6, preferably 0.12 to 0.5.

If the total mold content of acid and ester in the above copolymer is less than 0.5 mol%, the effect of improving the melt viscosity cannot be obtained;
Even if the copolymer exceeds T-ru%, not only the effect of stabilizing the melt viscosity is not further improved, but also the production cost of the copolymer becomes high and the production itself is difficult.

In addition, the composition ratio of acid and ester in the copolymer is 10 to 9.
Even outside the range of 0% to 90% to 10%, stabilization of the melt viscosity cannot be expected.

It is necessary that the above copolymer substantially contains α,β-unsaturated carboxylic acid alkyl ester units. α
, when there is substantially no β-unsaturated carboxylic acid ester unit, the composition of the saturated polyester If and the copolymer or a copolymer metal salt obtained by converting it into a metal salt has a high melt viscosity stability at high temperatures. No improvement in the composition was observed, and the uniformity of the composition also deteriorated.

If the intrinsic viscosity at 135° C. in decalin of the copolymer (B) is 0.01 or less, at least a part of the carboxylic acid units of the copolymer (B) and/or the copolymer (B) are replaced with a metal salt. The melt viscosity of the copolymer metal salt CB)' is low, making it difficult to uniformly mix them with the polyester resin. When the intrinsic viscosity exceeds 0.6, the effect of stabilizing the melt viscosity of the composition at high temperatures becomes small,
The fluidity of the composition also decreases.

The metal salt of the low molecular weight terpolymer, which is the component (B)' of the present invention, has at least a portion or all of the α,β-unsaturated carboxyl radical units in the low molecular weight terpolymer. It is obtained by reacting with a compound of a metal having a valence of 1 to 3!5.

The above-mentioned monovalent to trivalent metals include ■Na.

K, u, fvl, Ca, Ba, Zn
, Sb.

It is selected from Cu, Fe, ■Aj, Fe, and mixtures thereof, and among these, alkali metals are particularly preferred.

Its compounds include sodium hydroxide J magnesium hydroxide, potassium hydroxide, zinc hydroxide, calcium oxide,
Examples include sodium methoxide, sodium ethoxide, magnesium oxide, nickel acetate, sodium carbonate, magnesium acetate, and zinc acetate.

The reaction between these metal compounds and copolymers was
The method described in Japanese Patent No. 810, that is, the method of reacting a metal compound while heating and kneading the copolymer, or the method disclosed in Japanese Patent Application Laid-open No. 1983-79015, that is, ethylene-α,β-unsaturated Known methods are used, such as heating and degrading a carboxylic acid alkyl ester copolymer in the presence of water and metal ions in an inert atmosphere to form a low-molecular M terpolymer metal salt in one step. be done.

Among the various processes described above, at least one of the acrylic acid units of the ethylene-acrylic acid-ethyl acrylate copolymer obtained by thermally degrading the ethylene-ethyl acrylate copolymer produced by high-pressure radical polymerization method Most preferred is a metal salt of a low molecular weight M terpolymer in which a portion of the metal salt is a sodium salt.

The blending ratio of component (8) and component (B) and/or (B)' is as follows:
Or (B)' component is 0.2 to 30 parts by weight, preferably 1 to 2 G! This is the fi section. If the component (B) and/or (8)' is less than 0.2 parts by weight, little effect on improving the melt viscosity is observed, and if it exceeds 30 parts by weight, it will adversely affect the mechanical properties of the composition.

In the present invention, a filler substance (C) can be further blended in addition to the above-mentioned components (A), (B) and/or (B)'.

The amount of filler material (C) is 10 to 150 parts by weight.

If the above formulation m is less than 10 parts by weight, there is no improvement effect, and 1s
If it exceeds the 0mm portion, the mechanical strength will actually decrease. In addition, moldability also decreases.

As the filling material (C) of the present invention, inorganic or organic filling materials can be used. Specifically, calcium sulfate, calcium silicate, clay, diatomaceous earth, talc, alumina, silica sand, glass powder, iron oxide, metal powder, graphite, silicon carbide, silicon nitride, silica, boron nitride, aluminum nitride,
Powder-like fillers such as carbon black, mica, glass plates, sericite, pyrophyllite, metal foils such as aluminum flakes, flat or scaly fillers such as graphite, shirasu balloons, metal balloons, glass balloons, pumice. Hollow fillers such as glass 1a miscellaneous, carbon IN1 graphite mN1 whiskers, metal m*, silicon carbide fiber, asbestos, mineral II such as volus 1-night, etc.
Examples include N.

In particular, raIi materials such as glass fibers are preferred as they significantly improve mechanical properties. Further, the surface of the inorganic material is coated with fatty acids such as stearic acid, oleic acid, and balmicylic acid, or metal salts thereof, paraffin, wax, polyethylene wax, or modified products thereof, organic silane, inorganic borane, precipitated titanate, etc. It is preferable to perform surface treatments such as the following.

The composition of the present invention can be used in combination with conventionally used nucleating agents and crystallization promoters. Examples of these nucleating agents and crystallization promoters include inorganic compounds such as talc, clay, mica, and silica, sodium and potassium salts of organic carboxylic acids such as stearic acid and montanic acid, polynuclear cyclic compounds such as phenanthrene, and ionomers. be.

Further, customary additives such as flame retardants, ultraviolet absorbers, antioxidants, colorants, and hydrolysis-resistant agents may be added. Furthermore, other thermoplastic resins such as polyethylene, polypropylene, polycarbonate, polyamide, polyphenylene oxide, polyphenylene sulfide, polyarylene, polyether/etherketone, polystyrene, etc. may be blended.

The composition of the present invention is prepared by mixing the polyester resin (^), the low molecular group terpolymer (B) and/or (B)', and optionally inorganic fillers, additives, etc. in a Banbury mixer 1 pressure kneader. It is produced by melt-kneading using a commonly used mixer such as a single-kneading extruder, twin-screw extruder, or roll.

[Example] Examples of the present invention will be shown below.

115-" Ethylene-ethyl acrylate copolymer obtained by high-pressure radical polymerization, containing ffl 6.7 mol% of ethyl acrylate units, and having a melt index of 3.4 g/10 min as measured in accordance with JIS 6760. The polymer was continuously heat-degraded in the presence of water in a tubular reactor at a maximum temperature of 390°C, resulting in 95.1 mol% of ethylene units and 2.3 mol% of acrylic acid units.
An ethylene-acrylic acid-ethyl acrylate coelectrolyte was obtained, which contained 2.6 mol% of ethyl acrylate units and had an intrinsic viscosity of 0.17 in decalin at 135°C.

An aqueous solution of sodium hydroxide was added to this copolymer while heating and melt-kneading to obtain a copolymer metal salt (B)' in which 75% of the acrylic acid units in the copolymer were converted to sodium salts.

In phenol/tetrachloroethane mixture ff1W (weight ratio 1:1), intrinsic viscosity at 30°C 0.68
Polyethylene terephthalate resin (A) (hereinafter referred to as PET)
A composition was prepared by adding 5.31 parts of the above copolymer salt to the 100 parts (referred to as 100 parts) and melt-mixing them at 250°C for 5 minutes using a kneader.

Incidentally, PET and copolymer metal salt (B)' were all used in an absolutely dry state, including the following Examples and Comparative Examples.

To measure the melt viscosity, the composition was placed in a melt indexer controlled at 280°C and heated for 5 minutes and 30 minutes.
After holding at that temperature for a minute, it was extruded under a load of 5003 and the melt index was measured, and the results are shown in Table 1.

Example 2 The copolymer metal salt obtained in Example 1 was treated with the same P as in Example 1.
A composition was prepared in the same manner as in Example 1 by adding 1.5 parts of ET to 100 parts of ET, and the melt index was measured. The results are shown in Table 1.

Example 3 The ethylene-ethyl acrylate copolymer used in Example 1 was degraded by heating continuously at a high temperature of 390°C in the presence of water and sodium hydroxide in a tubular reactor to obtain ethylene units. 95.4 mol%, acrylic acid unit 3.1 mol% (of which 75% is sodium salt), ethyl acrylate unit 1
．． A copolymer metal salt having a concentration of 5 mol % was obtained.

When this copolymer metal salt was treated with an aqueous sulfuric acid solution and all the sodium salts were replaced with acrylic acid, the copolymer had an intrinsic viscosity of 0.26 in decalin at 135°C.

This copolymer metal salt was added to 8 parts by weight of PE7100 used in Example 1 and 5.0 parts by weight to prepare a composition in the same manner as in Example 1, and the melt index after 5 minutes and 30 minutes was was measured. The results are shown in Table 1.

Example 4 The ethylene-acrylic acid-ethyl acrylate copolymer obtained by heat degradation of the ethylene-ethyl acrylate copolymer in Example 1 was added to 4 parts by weight based on 100 parts by weight of PET used in Example 1. A composition was prepared in the same manner as in Example 1 by adding .0 parts by weight of ffi, and the melt index was measured after 5 minutes and 30 minutes. The results are shown in Table 1.

Example 5 Copolymer metal j! obtained in Example 1 was added to 100 parts by weight of PET used in Example 1. 3.9 parts by weight and 3 parts glass fiber
A composition was prepared by adding 0 parts by weight of ffi and melt-mixing at 250° C. for 5 minutes using a kneader.

The composition was placed in a melt indexer controlled at 280 DEG C., held at that temperature for 5 minutes and 30 minutes, and then a load of 12,160 g was applied to measure the extrusion melt index. As a result, the melt indenity after holding for 5 minutes was 9243 g/10 minutes, and the melt index after holding for 30 minutes was 429/10 minutes.

The melt index of the PET used in Example 1 was measured in the same manner as in Example 1.

The results are shown in Table 1.

Auditor' (-2) An ethylene-methyl methacrylate copolymer with a methyl methacrylate unit content of 4.2 mol% and an intrinsic viscosity of 0.75 at 135°C in decalin, obtained by high-pressure radical polymerization, was added to toluene. / isopropyl alcohol mixed solvent at 120°C with sodium hydroxide.The saponification reaction product was dispersed in water, sulfuric acid was added thereto, and a part of the sodium methacrylate salt units in the copolymer was dissolved into methacrylic acid. When dried and analyzed, it contained 9j ethylene units, 8 mol%, and 1 methacrylic acid unit.
．． 3 mol%, 1.7 mol% of sodium methacrylate salt units, and 1.2 mol% of methacrylic acid units.

5.0 parts by weight of the above copolymer base a salt was added to 100 parts by weight of PET used in Example 1, and a composition was prepared in the same manner as in Example 1, and the melt index was measured. The results are shown in Table 1.

Comparative Example 3 The same ethylene-ethyl acrylate copolymer used in Example 1 was heated at 360°C in the presence of water in a disposable reactor.
Degraded by heating at a temperature of 95.98 mol% of ethylene units,
Acrylic acid unit 4.0 mol%, ethyl acrylate unit 0
．． 02 mol % and an intrinsic viscosity of 0.08 at 135° C. in decalin was obtained.

An aqueous sodium hydroxide solution was added to this copolymer under heating and melt mixing to obtain a copolymer metal salt in which all of the acrylic acid units in the copolymer were made into sodium salts.

5.0 parts by weight of the copolymer metal salt was added to 100 parts by weight of the same PET used in Example 1, a composition was prepared in the same manner as in Example 1, and the melt index was measured. The results are shown in Table 1.

Comparative Example 4 The same ethylene-ethyl acrylate copolymer used in Example 1 was heated to 345 ml in the absence of water in a disposable reactor.
94.0 mol% of ethylene units by heating degradation at a temperature of ℃,
Acrylic acid unit 0.2 mol%, ethyl acrylate unit 5
．． A copolymer containing 9 mol % and having an intrinsic viscosity of 0.35 at 135° C. in decalin was obtained.

5.0 parts by weight of the above copolymer was added to 100 parts by weight of the same PET used in Example 1 to prepare a composition in the same manner as in Example 1, and the melt index was measured. The results are shown in Table 1.

Table 1 Note 1) Temperature: 280° C., load: soo g, suku) By Σ method [Effects of the Invention] The polyester resin composition of the present invention has excellent melt viscosity stability under heating, and therefore excellent molding stability.

Moreover, the composition has good fluidity and good moldability.

Furthermore, the composition of copolymer metal salt (B)' and polyester resin also has the characteristic of high crystallization rate.

Since the polyester resin composition of the present invention has the above-mentioned excellent properties, it is suitable for use in the field of injection molding of electric/electronic parts, automobile parts, etc., films, bottles, etc.

Claims (9)

[Claims] (1) At least saturated polyester resin (A) 100
80 to 99.5 mol% of ethylene, α,β-unsaturated carboxylic acid obtained by thermal degradation of a copolymer of relatively high molecular weight ethylene and α,β-unsaturated carboxylic acid alkyl ester in parts by weight. The total content of acid and α,β-unsaturated carboxylic acid alkyl ester is 0.5 to 20 mol%, and the composition ratio of the acid and alkyl ester is 10 to 90% to 90 to 90%.
10% and an intrinsic viscosity in the range of 0.07 to 0.6 in decalin at 135° C. and/or a carboxylic acid of the terpolymer (B). At least one part or all of the units have a valence of 1 to 3
A polyester resin composition containing 0.2 to 30 parts by weight of a copolymer salt (B) formed by reacting with a metal compound selected from the following. (2) 100 parts by weight of component (A), 0.2 to 30 parts by weight of components (B) and/or
) The polyester resin composition according to claim 1, comprising 10 to 150 parts by weight of . (3) The content of α,β-unsaturated carboxylic acid alkyl ester units in the relatively high molecular weight ethylene-α,β-unsaturated carboxylic acid alkyl ester copolymer is 0.5 to 2.
The polyester resin composition according to claim 1, which has a content of 5 mol %. (4) The polyester resin according to claim 3, wherein the alkyl group of the alkyl ester of the relatively high molecular weight ethylene-α,β-unsaturated carboxylic acid alkyl ester copolymer has 1 to 4 carbon atoms. Composition. (5) The relatively high molecular weight ethylene-α,β-unsaturated carboxylic acid alkyl ester copolymer is an ethylene-acrylic acid alkyl ester copolymer or an ethylene-alkyl methacrylate copolymer. 1
The polyester resin composition according to items 1 to 4. (6) Claim 5, wherein the ethylene-acrylic acid alkyl ester copolymer or ethylene-methacrylic acid alkyl ester copolymer is an ethylene-ethyl acrylate copolymer or an ethylene-methyl methacrylate copolymer. The polyester resin composition described. (7) The polyester resin composition according to claim 1, wherein the component (A) is polyethylene terephthalate. (8) The polyester resin composition according to claim 1, wherein the compound of a metal selected from monovalent to trivalent metals in component (B)' is a sodium compound. (9) The polyester resin composition according to claim 2, wherein the filler material of component (C) is glass fiber.