JPS6249310B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a resin composition, and more particularly to a glass fiber-reinforced polyethylene terephthalate resin composition that forms a molded article that has excellent moldability, particularly mold releasability, and embedding property, and has an excellent appearance, particularly gloss and whitening prevention. Reinforced resin compositions made by blending glass fibers with polyethylene terephthalate resin are well known. In other words, when polyethylene terephthalate resin is not blended with glass fiber, its impact resistance is particularly low, and its use as a so-called plastic molding material is limited, but by reinforcing it with glass fiber, it has significantly improved impact resistance. It has become clear that it can improve impact resistance, heat resistance, etc., and it has come to be widely used in electrical insulation parts, mechanical parts, etc. However, simply blending glass fiber with polyethylene terephthalate resin does not provide the desired properties as a molding material, and various improvements have been made and proposed.
For example, in order to increase the crystallization rate in the mold during injection molding, fine inorganic solid substances and organic substances that act as crystal nucleating agents are added to increase the density of the molded product and increase the temperature. It is known to improve dimensional stability over time. It has been reported in Japanese Patent Publication No. 46-29977 and Japanese Patent Publication No. 46-29977 that organic monocarboxylic acid metal salts, particularly sodium salts or potassium salts, are effective as such crystal nucleating agents.
It has been proposed in Publication No. 47-14502, Japanese Patent Publication No. 48-4098, etc. In addition, in order to improve the so-called mold releasability, which makes it easier to take out the molded product from the mold, and thereby shorten the molding cycle, compounds that have a mold release effect, for example, mainly carbon atoms of 20 to 32, are used. It has been proposed to incorporate an acid mixture of aliphatic monocarboxylic acids having a chain length of (hereinafter referred to as montan wax acid). However, there are few that satisfy both the crystal nucleation action and mold release action, and in particular, there are very few that can satisfy the injection molding conditions on an industrial scale. Therefore, it is desired to develop a technique that satisfies both the moldability and molded product properties of glass fiber-reinforced polyethylene terephthalate resin compositions. The inventor of the present invention has conducted various studies focusing on this point, and has found that the combination of the nucleation crystal forming agent and the mold release agent adversely affects each other, making it impossible to obtain the desired properties. We found that there are many For example, if the above-mentioned sodium salt or potassium salt of the organic monocarboxylic acid and montan wax acid are used simultaneously in polyethylene terephthalate resin, the degree of polymerization of the polyethylene terephthalate resin in the composition will be significantly reduced, and as a result, the strength of the molded product will be extremely low. It was found that the appearance characteristics, particularly the whitening phenomenon, were more likely to occur. This phenomenon is presumed to occur due to the acid decomposition of polyethylene terephthalate resin by montan wax acid, but the reaction may also be accelerated by the catalytic action of organic monocarboxylic acid sodium or potassium salts. It is estimated that this has a large influence. In such cases, it may be thought that it would be effective to use polyethylene terephthalate resin as a raw material in order to avoid a decrease in the strength of the molded product due to a decrease in the degree of polymerization of the polyethylene terephthalate resin, but in reality, Polyethylene terephthalate with a high degree of polymerization has a high viscosity when melted, and the decrease in the degree of polymerization by montan wax acid does not occur instantaneously, so when producing a composition, impregnation of the resin into glass fibers is difficult. As a result, the dispersibility of glass fibers is poor, resulting in a non-uniform molding material. Furthermore, as the melt viscosity increases, the kneading resistance increases, which causes greater damage to the glass fibers, which not only impairs the mechanical and thermal properties of the molded product, but also causes large local variations, causing the molded product to deteriorate. Depending on the intended use, this may often be a fatal defect that makes it unusable. As a result of repeated studies to develop a resin composition that does not cause such defects and has excellent crystallinity and mold release properties, the present inventor has found that the resin composition does not release easily from the sodium salt or potassium salt of an organic monocarboxylic acid alone. The inventors have discovered that this problem can be significantly improved by using a specific montan wax ester that does not have a mold effect, and have thus arrived at the present invention. That is, the present invention uses 5 to 200 parts by weight of glass fiber (B) and 2 to 28 carbon atoms per 100 parts by weight of polyethylene terephthalate resin (A) having an intrinsic viscosity (measured in an orthochlorophenol solution at 35°C) of 0.9 or less. 0.01 to 3 parts by weight of sodium salt or potassium salt (C) of organic monocarboxylic acid and the following formulas (1), (2) and (3) 50≦NV≦110 ………(1) 100≦SV≦180 … …(2) 0.05 to 3 parts by weight of montan wax ester (D) that satisfies 10≦SV−NV≦100 ………(3) (where NV is the neutralization value and SV is the saponification value). The present invention relates to a resin composition formed by blending the present invention. The polyethylene terephthalate resin as component (A) used in the present invention is polymerized using terephthalic acid or an ester-forming derivative of terephthalic acid as the acid component and ethylene glycol or an ester-forming derivative of ethylene glycol as the glycol component. Polymer. In this case, 20% each as acid component or glycol component.
Other types of dicarboxylic acids, glycols, or ester-forming derivatives thereof may be contained in a proportion of mol % or less. Examples of such other types of copolymerization components include isophthalic acid, naphthalene-2.
6-dicarboxylic acid, adipic acid, trimethylene glycol, tetramethylene glycol, neopentyl glycol, hexamethylene glycol, diethylene glycol, cyclohexanediol,
Examples thereof include cyclohexanedimethanol, 1,4-bisoxyethoxybenzene, bisphenol A, polyethylene ether glycol, polytetramethylene ether glycol, and ester-forming derivatives thereof. The intrinsic viscosity of polyethylene terephthalate resin is 0.9 or less, and even 0.4 as measured at 35°C using orthochlorophenol solvent.
~0.9, particularly preferably in the range of 0.45 to 0.8. When a polyethylene terephthalate resin with an intrinsic viscosity exceeding 0.9 is used, the fluidity of the composition is poor, and the resulting molded product not only loses its glossy appearance but also has large variations in its mechanical and thermal properties. So I don't like it. The glass fiber of component (B) used in the present invention is not particularly limited as long as it is generally used for reinforcing resins. For example, a long fiber type (glass roving) or a chopped strand of short fibers can be selected for use. Further, the glass fibers may be treated with a sizing agent (eg, polyvinyl acetate, polyester sizing agent, etc.), a coupling agent (eg, silane compound, borane compound, etc.), or other surface treatment agent. Furthermore, thermoplastic resin,
It may be coated with a resin such as a thermosetting resin.
Usually, long fiber type glass fibers are used by being cut into a desired length before or after blending with a resin, and this mode of use is also useful in the present invention. The amount of glass fiber added is preferably 5 to 200 parts by weight per 100 parts by weight of the polyethylene terephthalate resin. If the amount added is less than 5 parts by weight, the strength and heat resistance of the molded product will be low, and only an unsatisfactory molded product can be obtained. If the amount exceeds 200 parts by weight, the melt flowability of the composition will be markedly deteriorated, making it impossible to obtain a molded product with good appearance, and the strength will reach saturation, which is not preferable. The main part of the glass fiber length in the composition is 0.2mm.
It is preferable to use a material having a length of at least 100%. The sodium salt or potassium salt of an organic monocarboxylic acid as component (C) used in the present invention is a salt of an organic monocarboxylic acid represented by the formula R-COOH. Here, R is a hydrocarbon group of 1 to 27, and includes, for example, an alkyl group, a cyclic hydrocarbon group having a cyclo ring or a benzene ring, and an aralkyl group. Among these, R is preferably an alkyl group or an aryl group. Particularly preferred as the sodium or potassium salts of such organic monocarboxylic acids are sodium salts of saturated fatty acids such as acetic acid, propionic acid, caproic acid, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, etc. Or potassium salt, sodium salt or potassium salt of benzoic acid, etc. These salts act specifically as crystal nucleating agents for polyethylene terephthalate resin, and exhibit effects not found in other metal salts or compounds. Also, in combination with Montan wax ester, it exhibits an excellent mold release effect. The amount of the sodium salt or potassium salt of the organic monocarboxylic acid to be blended is preferably 0.01 to 3 parts by weight per 100 parts by weight of the polyethylene terephthalate resin. This amount is
When the amount is less than 0.01 part by weight, there is almost no effect as a crystal nucleating agent, while when it is used in an amount exceeding 3 parts by weight, the effect as a crystal nucleating agent is not increased. In fact, this is not preferable since it results in inhibiting the molecular weight reduction prevention effect of the polyethylene terephthalate resin according to the present invention. The montan wax ester of component (D) used in the present invention means a partial ester compound of montan wax acid. Here, montan wax acid is a mixture of saturated aliphatic monocarboxylic acids mainly having a chain length of 20 to 32 carbon atoms, and a common example is so-called montan wax obtained by refining lignite. ) is oxidized with an oxidizing agent such as a chromic acid mixture. The above-mentioned montan wax ester is prepared by converting the montanic acid into a monohydric or dihydric alcohol, particularly a dihydric alcohol having 2 to 4 carbon atoms in the alkylene group, according to the following formulas (1), (2) and (3). It is partially esterified to satisfy the following. 50≦NV≦110 ………(1) 100≦SV≦180 ………(2) 10≦SV−NV≦100 ………(3) (Here, NV is the neutralization value and SV is the saponification value. ) The above neutralization value and saponification value are values measured according to JISK3341. Unlike montanic acid, montan wax ester does not significantly reduce the molecular weight of polyethylene terephthalate resin, and when combined with a sodium salt or potassium salt of an organic monocarboxylic acid, exhibits an excellent mold release effect. The NV and SV of the montan wax ester greatly affect the mold releasability and physical property deterioration of the composition, particularly the molecular weight deterioration. As a condition for the release effect to occur, it is necessary for NV and SV to be within a certain range, as shown by the above formulas (1) and (2), but in addition, (SV - NV) must be within a certain range. The value must satisfy equation (3). When the (SV-NV) value is less than 10, the molecular weight of the polyethylene terephthalate resin decreases significantly, while when it exceeds 100, the release effect becomes extremely weak. The preferred range of (SV-NV) value is 20-80. The amount of Montan wax ester added is 0.05 to 100 parts by weight of polyethylene terephthalate resin.
It is 3 parts by weight. If the amount added is less than 0.05 parts by weight, there is almost no effect as a mold release agent, while if it is used in excess of 3 parts, the effect as a mold release agent reaches saturation and increases. Although this will not happen, it is impractical because it promotes a decrease in the molecular weight of the polyethylene terephthalate resin. The resin composition of the present invention is produced by blending a polyethylene terephthalate resin, glass fiber, a sodium salt or potassium salt of an organic monocarboxylic acid, and a montan wax ester. Any method can be used for the blending method.
Generally, it is preferable to disperse these components more uniformly, for example, by mixing all of them simultaneously or separately using a blender, kneader, roll, extruder, etc., and homogenizing them, or by simultaneously dispersing some of the mixed components. Alternatively, they are mixed separately, for example, in a blender, kneader, roll, extruder, etc., and the remaining components are further mixed in these mixers or extruders,
Homogenization methods can be used. Furthermore,
The montan wax ester is preferably kneaded into the polyethylene terephthalate resin, and it is preferable to melt and mix the two in advance. The most common method is to melt and knead a previously dry-blended composition in a heated extruder to homogenize it, extrude it into wires, and then cut it into desired lengths and granulate it. . The molding composition thus prepared is normally kept in a sufficiently dry state before being charged into the hopper of a molding machine and subjected to molding. Other methods include, for example, a method in which other components are added or mixed during the production of polyethylene terephthalate, before the polycondensation, after the polycondensation, or during the polycondensation. Glass fibers may be dry blended without being melt-kneaded with other components in an extruder in order to prevent the glass fibers from shattering as much as possible during kneading and to improve workability during composition production. For example, a composition obtained by mixing glass fiber-free polyethylene terephthalate granules produced in an extruder with a predetermined amount of glass chopped strands or a pre-prepared glass fiber-rich thermoplastic resin is placed in a molding machine hopper. It can also be used for molding. Pigments and other compounding agents may be added to the composition of the present invention in the desired amount. Examples of such compounding agents include flame retardants such as halogen-containing compounds such as brominated biphenyl ether, brominated bisphenol-A diglycidyl ether, and polycarbonate oligomers produced from brominated bisphenol-A; red phosphorus; Phosphorus compounds such as triphenyl phosphate; phosphorus-nitrogen compounds such as phosphonic acid amides; flame retardant aids such as antimony trioxide and zinc borate; inorganic substances as nucleating agents that further promote crystallization, such as alkaline earth. Examples include metal carbonates (eg, calcium carbonate, magnesium carbonate, etc.), sulfates (eg, calcium sulfate, etc.), metal oxides such as titanium oxide, aluminum oxide, zinc oxide, etc., talc, graphite, aluminum silicate, clay, and the like. Furthermore, inorganic fillers such as silica, mica, asbestos, glass Fuchs glass powder, potassium titanate, carbon fiber, feldspar, etc., and other stabilizers,
Colorants, antioxidants, lubricants, ultraviolet absorbers, and antistatic agents can also be added. Also, in small proportions, other thermoplastic resins such as styrene resins, acrylic resins, polyethylene, polypropylene, fluorine resins, polyamide resins, polycarbonate resins, polysulfones, etc.; thermosetting resins such as phenolic resins, melamine resins, unsaturated polyester resins , silicone resins, etc.; and soft thermoplastic resins such as ethylene-vinyl acetate copolymers, polyester elastomers, ethylene-propylene terpolymers, etc. may also be added. The resin composition of the present invention can be molded very easily by a conventional method using a general thermoplastic resin molding machine. There is no need to particularly heat the mold temperature, but when molding is performed in a mold preheated to 120℃ to 150℃, the crystallization rate is accelerated by the effect of the nucleating agent, resulting in more homogeneous molding both inside and outside. This is preferable because it allows you to obtain products. The resin composition of the present invention has excellent moldability (particularly embeddability, crystallinity, and mold releasability), and can be molded into molded products with high productivity, and the resulting molded products have excellent optical selectivity and whiteness. This phenomenon (the phenomenon of white powdery matter adhering to the surface of the molded product) is prevented, and not only does it have an excellent appearance, but it also suppresses the decrease in the molecular weight of the resin, so it exhibits the desired mechanical and thermal properties. can do. The present invention will be further explained below with reference to Examples. In the examples, the intrinsic viscosity of the polyethylene terephthalate resin and polybutylene terephthalate resin is the value measured in orthochlorophenol at 35°C.
Moreover, the mold releasability and static strength during molding are values measured by the following method unless otherwise specified. Mold releasability: After drying the sample molding pellets with hot air at 140℃ for 4 hours, they were immediately put into a 5-ounce injection molding machine at a cylinder temperature of 275℃, an injection pressure of 800Kg/cm ² , and a mold temperature.
A box-shaped molded product (external dimensions: bottom 128 mm x 68 mm, height 39 mm, wall thickness 2 mm) is molded under the molding conditions of 140°C, cooling time 25 seconds, and total cycle 40 seconds. The molding machine used in this test was equipped with a dynamic strain measuring device (Strong Gauge) between the extrusion plate and the extrusion pin.
After the cycle is completed and the mold is opened, the force required to release the molded product (referred to as mold release force) can be detected by a dynamic strain measuring device via the mold knockout pin and the molding machine extrusion pin. It's like this. Therefore, the degree of difficulty in mold releasability can be indicated by the value of the mold release force. However, in reality, when the mold is opened without any charge of resin in the mold, the force detected by the dynamic strain measuring instrument is 0.5 kg, which is less than the force required to release the molded product itself. The force is (measured value - 0.5) Kg - weight. This numerical value is called a mold release index and is used as a numerical value representing the degree of mold releasability. That is, the smaller the mold release index is, the better the mold release property is. The measured value of the mold release index is determined by measuring the mold release force for 10 shots of the molded product from the 11th shot to the 20th shot after the start of continuous molding.
It is shown as the value obtained by subtracting 0.5 from the average value (unit: kg - weight). Static strength: After drying the sample molding pellet with hot air at 140℃ for 4 hours, a test piece mold for measuring physical properties was attached to a 5-ounce injection molding machine, and the cylinder temperature was
Test pieces were molded under the following conditions: 280° C., mold temperature 140° C., injection pressure 1000 Kg/cm ² , cooling time 20 seconds, and total cycle 35 seconds. A tensile test (ASTM D-638) and a bending test (ASTM D790) were conducted using this test piece. Examples 1 and 2 and Comparative Examples 1 to 5 70 parts by weight of polyethylene terephthalate resin with an intrinsic viscosity of 0.64 dried at 120°C for 5 hours and a length of 3 mm
30 parts by weight of glass chopped strands and table-
The various mold release agents shown in Table 1 were added in the parts by weight shown in Table 1 and mixed uniformly using a V-type blender. This mixture was processed using a 65mmφ extruder at a barrel temperature of 280°C.
The mixture was melted and mixed at ℃, and the threads released from the die were cooled and cut to obtain pellets for molding. Next, 0.1 weight of sodium acetate powder was added to 100 parts by weight of the pellets, and the pellets were mixed uniformly using a V-type blender and then subjected to molding. Mold releasability during molding of each pellet,
The measurement results of the intrinsic viscosity and static strength of the molded product are shown below.
They are summarized in 1. All of the molded products obtained here have excellent surface appearance and are equally shiny and beautiful, but the mold releasability and static strength vary depending on the mold release agent used and the amount added. was gotten.

【table】

[Table] The mold release agent used in Comparative Example 1, WAX-S (manufactured by Hoechst AG, West Germany), is the montan wax acid described herein. When this WAX-S is used, the mold releasability is extremely good, but it has the disadvantage that the intrinsic viscosity of the molded product is significantly lowered, and the static strength of the molded product is thereby greatly reduced. On the other hand, if WAX-S is reacted with 1,3-butanediol to esterify some of the carboxyl groups and used as a mold release agent, the degree of esterification will affect mold releasability and static strength. changes greatly. That is, the embodiments of Examples 1 and 2 are partially esterified according to the present invention, and WAX-
0.35 equivalent and 0.5 equivalent of 1.
It is esterified with 3-butanediol. It can be seen that when these esterified products are used as mold release agents, both mold releasability and static strength are good. However, in the embodiment of Comparative Example 2 in which WAX-S was partially esterified by reacting with 0.83 equivalents of 1,3-butanediol, no decrease in static strength was observed, but the mold releasability was extremely poor, and the molded product could not be released. It swelled greatly due to the pressure of the mold dowel pin during molding. Comparative example 3
This is an embodiment in which a large amount of the esterified product of WAX-S used in Example 1 was added. In this case, there was no problem with mold releasability, but a significant decrease in static strength was observed. Further, Comparative Examples 4 and 5 are examples in which stearic acid and an esterification of stearic acid with 0.7 equivalent of 1,3-butanediol were used as mold release agents. However, in both cases, the releasability was extremely poor. In particular, in systems containing stearic acid, the intrinsic viscosity of molded products decreases and the static strength is also low. Comparative Examples 6 and 7 70 parts by weight of polybutylene terephthalate resin with an intrinsic viscosity of 0.90 dried at 130°C for 3 hours with a length of 3 mm
30 parts by weight of glass chopped strands and WAX-S used in Comparative Example 1 or WAX-S used in Comparative Example 2
0.3 parts by weight of 1,3-butanediol partial ester of WAX-S was added and mixed and blended uniformly in advance. This mixture was kneaded and extruded using a 30 mmφ vented extruder while degassing from the vent part. The barrel temperature during extrusion was 270°C, and the average discharge amount was about 2 kg/. The extrudate was passed through cooling water and then cut with a cutter to obtain pellets for molding. Sodium acetate powder per 100 parts by weight of the pellets
0.1 part by weight was added and mixed uniformly using a V-type blender, followed by molding. The molding was performed under the same molding conditions as in Example 1, except that the cylinder temperature of the molding machine during molding was set at 250°C, and the mold releasability and static strength were measured. The measurement results are shown in Table-
As shown in 2.

[Table] According to this, the case of polybutylene terephthalate resin is similar to the case of polyethylene terephthalate resin shown in Comparative Example 1 and Comparative Example 2.
It can be seen that the static strength decreases when WAX-S is used. However, the great achievement of both is WAX−
It can be seen that when an esterified product of S is added, the compound has an extremely low mold release effect on polyethylene terephthalate resin, but exhibits a large mold release effect on polybutylene terephthalate resin. That is, when the esterification rate of the Montan wax according to the present invention is different, the influence on the mold release properties of the composition is greater for polyethylene terephthalate resin and polybutylene terephthalate resin among terephthalate esters that are polymers belonging to the same family. Different. Therefore, the neutralization value and saponification value of the montan wax acid ester specified in the present invention are applicable only to polyethylene terephthalate resin. Example 3 100 parts by weight of polyethylene terephthalate with an intrinsic viscosity of 0.72, dried at 120°C for 5 hours, fiber length 3 mm
Glass chopped strand 42 parts by weight WAX−
0.3 parts by weight of an esterified product obtained by partially esterifying S with 0.5 equivalents of n-butanol and 0.15 parts by weight of sodium stearate were mixed uniformly in a tumbler in advance, and then extruded and kneaded under the same conditions as Example 1 for molding. Got pellets. The WAX-S esterified product used as a mold release agent had a neutralization value of 65 and a saponification value of 143. The appearance of molded products made using the pellets was glossy and extremely good. Moreover, the measurement results of mold release index and static strength are as follows. Mold release index: 12Kg/heavy tensile strength: 1540Kg/cm ² Bending strength: 2030Kg/cm ² Flexural modulus: 97000Kg/cm ² Example 4 100 parts by weight of polyethylene terephthalate with an intrinsic viscosity of 0.72, dried at 120°C for 5 hours, Fiber length 3mm
14 parts by weight of glass chopped strands, talc
28 parts by weight, potassium benzoate 0.15 parts by weight, and
0.3 parts by weight of an esterified product (neutralization value: 69, saponification value: 153) obtained by partially esterifying WAX-S with 0.4 equivalents of ethylene glycol was mixed uniformly in advance in a V-type blender, and then under the same conditions as Example 1. The mixture was extruded and kneaded to obtain pellets for molding. As a result of molding using the pellets, the mold releasability during molding was extremely good, and no problems occurred during molding. Furthermore, the appearance of the obtained molded product was excellent in gloss and had a beautiful surface condition. The measurement results of the mold release index during molding, the intrinsic viscosity of the molded product, and the static strength of the molded product are shown below. Mold release index: 4Kg/heavy tensile strength: 1010Kg/cm ² Bending strength: 1390Kg/cm ² Intrinsic viscosity of molded product: 0.65

Claims (1)

[Claims] 1. Intrinsic viscosity (35 in orthochlorophenol solution)
(measured at °C) 0.9 or less per 100 parts by weight of polyethylene terephthalate resin (A), 5 to 200 parts by weight of glass fiber (B), and 0.01 part of sodium or potassium salt of an organic monocarboxylic acid having 2 to 28 carbon atoms (C). ~3 parts by weight, and the following formulas (1), (2) and (3) 50≦NV≦110 ………(1) 100≦SV≦180 ………(2) 10≦SV−NV≦100 … ...(3) A resin composition containing 0.05 to 3 parts by weight of montan wax ester (D) that satisfies the following (where NV is a neutralization value and SV is a saponification value).