JPH0243236A - Ultrahigh-molecular-weight polyolefin composition - Google Patents

Abstract

PURPOSE:To provide the title compsn. having excellent heat stability and providing a molecularly oriented molding with excellent tensile strength, etc., by compounding an ultrahigh-MW polyolefin of a specified viscosity with specified amt. of a diluent and an org. thioether stabilizer. CONSTITUTION:An ultrahigh-MW polyolefin compsn. is prepd. by mixing 3-80wt.% ultrahigh-MW polyolefin (A) having an intrinsic viscosity of 5-40dl/g as measured in decalin solvent at 135 deg.C (e.g., an ultrahigh-MW polyethylene), 97-20wt.% diluent (B) (e.g., paraffin wax) and 0.005-5 pts.wt. org. thioether stabilizer (e.g., dilauryl thiodipropionate) based on 100 pts.wt. sum of the component A and B. As this compsn. scarcely undergoes thermal deterioration while molding, a molecularly oriented fiber, etc., obtd. by molding, exhibit excellent tensile strength, tensile elastic modulus, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to an ultra-high molecular weight polyolefin composition suitable for obtaining a molecularly oriented molded article, and more specifically to an ultra-high molecular weight polyolefin composition that has excellent thermal stability during molding and long-term thermal stability. The present invention relates to an ultra-high molecular weight polyolefin composition for molding a molecularly oriented molded article.

Technical background of the invention and its problems It is already known that a molecularly oriented molded article having high tensile strength and high tensile modulus can be obtained by forming an ultra-high molecular weight polyolefin into a fiber, tape, etc. and then stretching it. ing. For example, JP-A-56-15408 discloses a method of spinning a dilute solution of ultra-high molecular weight polyethylene and then drawing the resulting filament.

Further, JP-A-59-130313 discloses a method in which ultra-high molecular weight polyethylene and wax are melt-kneaded, the kneaded product is extruded, the kneaded product is then cooled and solidified, and then stretched. Furthermore, JP-A-59-187614
The publication discloses a method in which the melt-kneaded product is extruded and then passed through a draft, and then the melt-kneaded product is cooled, solidified, and stretched.

In this way, fibers using ultra-high molecular weight polyolefins,
When molding a molecularly oriented molded product such as a tape, a dilute solution of ultra-high molecular weight polyolefin is spun and the resulting filament is drawn, or a mixture of ultra-high molecular weight polyolefin and a diluent such as wax is melted. It is necessary to perform operations such as extruding the kneaded material after kneading, and then cooling and solidifying the mixed wire material and stretching it. During such operations, ultra-high molecular weight polyolefins may suffer from thermal stability during molding, such as being kept in a dilute solution at high temperatures for long periods of time, or undergoing thermal deterioration through extrusion in a high-temperature extruder. Because of the poor properties, the tensile strength, tensile modulus, etc. of the resulting molecularly oriented molded product were not necessarily sufficient.

Further, the above-mentioned ultra-high molecular weight polyolefin compositions all have a problem in that they are inferior not only in thermal stability during molding but also in long-term thermal stability.

Purpose of the Invention The present invention aims to solve the above-mentioned problems, and provides a molecularly oriented molded product that does not impair the tensile strength, tensile modulus, etc. inherent to ultra-high molecular weight polyolefins. The object of the present invention is to provide an ultra-high molecular weight polyolefin composition that has excellent heat stability during molding and long-term heat resistance stability suitable for obtaining.

Summary of the Invention The first ultra-high molecular weight polyolefin composition according to the present invention has (A) an intrinsic viscosity [η] of 5 to 40 dJ at 71-1 in a decalin solvent at 135°C. /g of ultra-high molecular weight polyolefin = 3 to 80% by weight, and (B) diluent = 97 to 2
and (C) organic thioether stabilizer = 0.005 to 5 parts by weight based on 100 parts by weight of the total weight of (A) ultra-high molecular weight polyolefin and (B) diluent. There is.

Further, the second ultra-high molecular weight polyolefin composition according to the present invention has (A) an intrinsic viscosity [η
] is 5 to 40 dg/g, 23 to 80% by weight of an ultra-high molecular weight polyolefin, and (B) diluent: 97 to 20% by weight.
and (C) organic thioether stabilizer: 0.005 to 5 parts by weight based on 100 parts by weight of the total weight of (A) ultra-high molecular weight polyolefin and (B) diluent, and (D) metal salt of higher fatty acid. (2) It is characterized by comprising 0.005 to 5 parts by weight based on 100 parts by weight of the total weight of (A) ultra-high molecular weight polyolefin and (B) diluent.

DETAILED DESCRIPTION OF THE INVENTION The ultra-high molecular weight polyolefin composition according to the present invention will be specifically described below.

Ultra-high molecular weight polyolefin (A) The intrinsic viscosity [η] of the ultra-high molecular weight polyolefin (A) used in the present invention measured in a decalin solvent at 135°C is:
At least 5d, l! /g, preferably 5-40dR/
It is g. If the intrinsic viscosity [η] is less than 5 dl/g, the resulting molecularly oriented molded product will not have sufficient tensile strength, while if it exceeds 40 dl/g, it will tend to be difficult to mold the molecularly oriented molded product. I don't like it because of this.

The ultra-high molecular weight polyolefin (A) as described above is, for example, ethylene, propylene, l-butene, l-pentene, ■-hexene, 1-octene, ■-decene, ■-dodecene, 4-methyl-1-pentene, It consists of a homopolymer or copolymer of α-olefin such as 3-methyl-1-pentene. Among these, ethylene homopolymers or copolymers of ethylene and other α-olefins, with ethylene as the main component, are particularly preferred.

In the ultra-high molecular weight polyolefin composition according to the present invention, the ultra-high molecular weight polyolefin and the diluent (B) described below are such that the ultra-high molecular weight polyolefin (A) is the sum of both components (A) and (B). It is present in a proportion of 3 to 80% by weight. The ultra-high molecular weight polyolefin as described above is preferably present in a proportion of 15 to 60% by weight based on the total weight of component (A) and component (B). If the amount of the ultra-high molecular weight polyolefin (A) is less than 3% by weight, it is undesirable because melt cross-wire becomes difficult and the stretchability of the molded product tends to be poor, while if it exceeds 80% by weight, the melt viscosity This is not preferable because it becomes too high, making melt cross-wire or melt molding difficult, and the surface of the molded product is markedly rough, and it is likely to cause stretching breakage, etc.

Diluent (B) The ultra-high molecular weight polyolefin composition according to the present invention contains a diluent (B) in addition to the above-mentioned ultra-high molecular weight polyolefin (A).

As the diluent, a solvent for ultra-high molecular weight polyolefin or various waxes having dispersibility for ultra-high molecular weight polyolefin are used.

The solvent used as the diluent (B) in the present invention is preferably a solvent having a boiling point higher than the melting point of the ultra-high molecular weight polyolefin, more preferably higher than the melting point +20°C.

Specifically, such solvents include n-nonane, n-
-dodecane, n-undecane, n-tetradecane, n-
Octadecane or liquid paraffin, aliphatic hydrocarbon solvents such as kerosene, xylene, naphthalene, tetralin,
Aromatic hydrocarbon solvents such as butylbenzene, p-cymene, cyclohexylbenzene, diethylbenzene, pentylbenzene, dodecylbenzene, bicyclohexyl, decalin, methylnaphthalene, ethylnaphthalene or hydrogenated derivatives thereof, 1, 1, 2. 2-tetrachloroethane, pentachloroethane, hexachloroethane, 1,2
．． 3-trichloropropane, dichlorobenzene, 1,2
．． Examples include halogenated hydrocarbon solvents such as 4-trichlorobenzene and bromobenzene, mineral oils such as paraffinic process oils, naphthenic process oils, and aromatic process oils.

Further, as the wax used as the diluent (B) in the present invention, an aliphatic hydrocarbon compound or a derivative thereof is used.

The aliphatic hydrocarbon compound is a paraffin wax mainly composed of a saturated aliphatic hydrocarbon compound, and usually has a molecular weight of 2,000 or less, preferably 1,000 or less, and more preferably 800 or less. Specifically, the following aliphatic hydrocarbon compounds are used.

N-alkanes with 22 or more carbon atoms such as tocosan, tricosane, tetracosane, and triacontane, or mixtures of these with lower n-alkanes as main components, so-called paraffin wax separated and refined from petroleum, ethylene or ethylene and other Polyethylene such as medium/low pressure polyethylene wax, high pressure polyethylene wax, ethylene copolymer wax, medium/low pressure polyethylene, high pressure polyethylene, etc., which are low molecular weight polymers obtained by copolymerizing with α-olefin, is thermally degraded. Waxes with lower molecular weights, oxides of these waxes, oxidized waxes modified with maleic acid, waxes modified with maleic acid, etc.

Examples of aliphatic hydrocarbon compound derivatives include one or more, preferably one to two, particularly preferably one, carboxyl group or hydroxyl group at the terminal or inside of an aliphatic hydrocarbon group (alkyl group, alkenyl group). , a compound having a functional group such as a carbamoyl group, an ester group, a mercapto group, a carbonyl group, etc., with a carbon number of 8 or more, preferably a carbon number of 12 to 50, or a molecular weight of 130 to 2,000. Preferably 200 to 800 fatty acids, fatty alcohols,
Fatty acid amides, fatty acid esters, aliphatic mercaptans,
Aliphatic aldehydes, aliphatic ketones, etc. are used. Specifically, the following compounds are used.

Fatty acids such as capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and oleic acid, aliphatic alcohols such as lauryl alcohol, myristyl alcohol, cetyl alcohol, and stearyl alcohol, caprinamide, lauramide, valmitinamide, stearylamide, etc. Fatty acid amide, fatty acid ester such as stearyl acetate, etc.

In the ultra-high molecular weight polyolefin composition according to the present invention, the ultra-high molecular weight polyolefin and the diluent (B) are such that the diluent (B) is based on the total weight of both components (A) and (B). It is present in a proportion of 97 to 20% by weight. The diluent (B) as described above is preferably present in a proportion of 85 to 40% by weight based on the total weight of component (A) and component (B). If the amount of the diluent (B) is less than 20% by weight, the melt viscosity becomes too high, making melt cross-wire or melt molding difficult, and the surface of the molded product becomes markedly rough, and it is likely to cause stretching breakage, etc., so it is preferable. On the other hand, if it exceeds 97% by weight, it becomes difficult to melt and knead and the stretchability of the molded product tends to be poor, which is not preferable.

Organic thioether stabilizer (C) The ultra-high molecular weight polyolefin composition according to the present invention contains an organic thioether stabilizer (C) in addition to the above-mentioned ultra-high molecular weight polyolefin (A) and diluent (B). Contains.

As the organic thioether stabilizer, conventionally known stabilizers can be used without particular restriction, and specifically, the following compounds are used.

Dialkylthiodipropionates such as dilauryl-simyristyl-distearyl and butyl-, octyl-
Examples include esters of polyhydric alcohols (eg, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, trishydroxyethyl isocyanurate) of alkylthiopropionic acids such as lauryl-stearyl (eg, pentaerythritol tetralaurylthioprobionate).

More specifically, dilaurylthiodipropionate,
Simyristylthiodipropionate, distearylthiodipropionate, laurylstearylthiodipropionate, distearylthiodibutyrate, etc.

These organic thioether stabilizers may be used alone or in combination.

In the ultra-high molecular weight polyolefin composition according to the present invention, the organic thioether stabilizer (C) as described above is contained at 0 parts by weight based on 100 parts by weight of the total weight of the ultra-high molecular weight polyolefin (A) and the diluent (B). .005 to 5 parts by weight, preferably 0.01 to 0.5 parts by weight, more preferably 0.05 parts by weight
It is used in an amount of ˜0.2 parts by weight. The amount of this organic thioether stabilizer (C) is
) and diluent (B), based on 100 parts by weight of the total weight.
．． If the amount is less than 0.005 parts by weight, the effect of improving heat resistance will be low, which is undesirable, while if it exceeds 5 parts by weight, not only will the cost of the stabilizer increase, but the properties of the resin, such as tensile elongation, may be impaired. This is not desirable because of the

Metal salt of higher fatty acid (D) The ultra-high molecular weight polyolefin composition according to the present invention comprises the above-mentioned ultra-high molecular weight polyolefin (A), a diluent (B
) and an organic thioether stabilizer (C), it contains a metal salt of a higher fatty acid (D).

Examples of metal salts of higher fatty acids include magnesium salts and calcium salts of higher fatty acids such as stearic acid, oleic acid, lauric acid, capric acid, araxic acid, valmitic acid, behenic acid, 12-hydroxystearic acid, ricinoleic acid, and montanic acid. , alkaline earth metal salts such as barium salts, alkali metal salts such as cadmium salts, zinc salts, lead salts, sodium salts, and potassium-lithium salts. Specifically, the following compounds are used.

Magnesium stearate, magnesium laurate,
Magnesium palmitate, calcium stearate,
Calcium oleate, calcium laurate, barium stearate, barium oleate, barium laurate, barium araxinate, barium behenate, zinc stearate, zinc oleate, zinc laurate, stearate, sodium stearate, valmitic acid Sodium, sodium laurate, potassium stearate, potassium laurate, calcium 12-hydroxystearate, calcium montanate, etc.

These metal salts of higher fatty acids may be used alone or in combination.

In the ultra-high molecular weight polyolefin composition according to the present invention, the metal salt of higher fatty acid (D) as described above is added to the ultra-high molecular weight polyolefin (A) and the diluent (B) in a total amount of
0.005-5 parts by weight, preferably 0
．． 01 to 0.5 parts by weight, more preferably 0.05 to 0
．． It is used in an amount of 5 parts by weight. When the amount of the higher fatty acid metal salt (D) is less than 0.005 parts by weight based on 100 parts by weight of the total weight of the ultra-high molecular weight polyolefin (A) and the diluent (B), the polymer derived from the catalyst Absorption of residual chlorine in the stabilizer is not sufficient and causes resin deterioration, which is undesirable.On the other hand, if it exceeds 5 parts by weight, not only will the cost of the stabilizer increase, but the properties of the resin, such as tensile elongation, will be impaired. This is not desirable as there is a risk of being exposed.

The metal salts of higher fatty acids as described above have effects as lubricants and antirust agents, so the ultrahigh molecular weight polyolefin composition according to the present invention has excellent moldability and is effective in preventing rust in molding machines, etc. .

In addition to the above-mentioned components (A), (B), (C) and (D), the ultra-high molecular weight polyolefin composition according to the present invention includes, for example, heat stabilizers, weather stabilizers, pigments, dyes, lubricants, Compounding agents such as antistatic agents that are usually added to polyolefins can be added within the range that does not impair the purpose of the present invention.

Effects of the Invention The ultra-high molecular weight polyolefin composition according to the present invention has excellent thermal stability during molding and long-term heat resistance stability, and suffers little thermal deterioration when molding molecularly oriented molded articles such as fibers and tapes. It can be used to produce molecularly oriented molded articles having high tensile strength, high tensile modulus, etc.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 Ultra-high molecular weight polyethylene (intrinsic viscosity [η] -8,94d
11/g, measured in decalin solvent at 135°C) powder and 80 parts by weight of paraffin wax (manufactured by Nippon Seiro Co., Ltd., trade name Nilpax, melting point: 69°C) as a diluent, and an organic thioether-based As a stabilizer, 0.1 weight part of dilauryl thiodipropionate (manufactured by NOF ■, trade name: Antiox L) was mixed and melt-spun under the following conditions.

The mixture was passed through a screw extruder (screw diameter 25 mm,
L/D-25, manufactured by Thermoplastics Department),
After melt mixing was performed at a set temperature of 190° C., the melt was melt-spun using a spinning die with an orifice diameter of 2I+I11 attached to an extruder. Next, the extruded melt was taken under the conditions of an air gap of 180 marks and a draft ratio of 35 times, and was cooled and solidified in air to obtain an undrawn fiber.

Furthermore, the undrawn fibers were drawn under the following conditions to obtain molecularly oriented fibers.

Two-stage stretching was performed using a Godetstrol made by Ohdai. At this time, the heating medium in the first drawing tank was n-decane at a temperature of 110°C, and the heating medium in the second drawing tank was triethylene glycol at a temperature of 145°C. The effective length of each tank was 501+. During stretching, the rotation speed of the first godet roll was 0.5/min, and the rotation speed of the third godet roll was 12.5/min (stretching ratio: 25 times).

The rotational speed of the second godet roll was appropriately selected within a range that allowed stable operation. Almost all of the initially mixed paraffin wax was extracted into n-decane during stretching.

Next, the obtained molecularly oriented fibers were washed with water, dried under reduced pressure at room temperature for a day and night, and subjected to measurements of intrinsic viscosity [η] and tensile properties. These measurement methods are as follows.

Intrinsic viscosity [η]: Intrinsic viscosity of resin constituting molecularly oriented fibers measured in decalin solvent at 135°C.Tensile properties: Elastic modulus and tensile strength were measured as tensile properties using a Shimadzu DC3-50M tensile tester. , measured at room temperature (23°C). At this time, the test length between the clamps was 100III11, and the tensile speed was 100 m/min (100 m/min).
% strain rate). The elastic modulus was calculated using the slope of the tangent at the initial elastic modulus. The fiber cross-sectional area required for calculation is density 0.960
It was calculated from the weight as g/cc.

The results are shown in Table 1.

Implementation ftJ2 In Example 1, as the organic thioether stabilizer,
Using 0.1 part by weight of dilauryl thiodipropionate (manufactured by NOF ■, trade name: Antioxshi), further,
Example 1 except that 0.3 parts by weight of calcium stearate (manufactured by Sankyoki ■) was added as a higher fatty acid metal salt.
Molecularly oriented fibers were obtained in the same manner as above, and the measurements described above were performed.

The results are shown in Table 1.

Example 3 In Example 1, as the organic thioether stabilizer,
Molecularly oriented fibers were obtained in the same manner as in Example 1, except that 0.1 part by weight of distearyl thiodipropionate (manufactured by Yoshitomi Pharmaceutical ■, trade name: DSTP r Yoshitomi) was used.
The above measurements were carried out.

The results are shown in Table 1.

Example 4 In Example 1, as the organic thioether stabilizer,
0.1 part by weight of distearyl thiodipropionate (manufactured by Yoshitomi Pharmaceutical ■, trade name: DSTP r Yoshitomi) was used, and 0.3 part by weight of calcium stearate (manufactured by Sankyoki ■) was used as a higher fatty acid metal salt. Molecularly oriented fibers were obtained in the same manner as in Example 1, except that the above-mentioned measurements were carried out.

The results are shown in Table 1.

Example 5 In Example 1, as the organic thioether stabilizer,
Lauryl stearyl thiodipropionate (Yoshitomi Pharmaceutical ■
Molecularly oriented fibers were obtained in the same manner as in Example 1, except that 0.1 part by weight of LSTP r Yoshitomi (trade name: LSTP r Yoshitomi) was used, and the δp1 constant was determined.

The results are shown in Table 1.

Example 6 In Example 1, as the organic thioether stabilizer,
Lauryl stearyl thiodipropionate (Yoshitomi Pharmaceutical ■
Example 1 except that 0.1 part by weight of LSTP r Yoshitomi (manufactured by Manufacturer, trade name: LSTP r Yoshitomi) was used, and 0.3 part by weight of calcium stearate (manufactured by Sankyoki ■) was added as a higher fatty acid metal salt. In the same manner, molecularly oriented fibers were obtained and the measurements described above were performed.

The results are shown in Table 1.

Example 7 In Example 1, as the organic thioether stabilizer,
Molecularly oriented fibers were obtained in the same manner as in Example 1, except that 0.1 part by weight of pentaerythrityl tetra-β-mercaptrauryl propionate (manufactured by Cipro Kasei ■, trade name Nijinox 412S) was used. The above measurements were carried out.

The results are shown in Table 1.

Example 8 In Example 1, as the organic thioether stabilizer,
Using 0.1 part by weight of pentaerythrityl tetra-β-mercaptrauryl propionate (Cipro Kasei vIJa, trade name Nijinox 412S), calcium stearate (Sankyoki) was added as a higher fatty acid metal salt.
Molecularly oriented fibers were obtained in the same manner as in Example 1, except that 0.3 parts by weight of (manufactured by) Co., Ltd.) was added, and the 711j determination described above was performed.

The results are shown in Table 1.

Example 9 In Example 1, as the organic thioether stabilizer,
Molecularly oriented fibers were obtained in the same manner as in Example 1, except that 0.1 part by weight of cimilistyl thiodipropionate (manufactured by Yoshitomi Pharmaceutical ■, trade name: DMTP r Yoshitomi) was used.
The above n1 determination was performed.

The results are shown in Table 1.

Example 10 In Example 1, as the organic thioether stabilizer,
Using 0.1 part by weight of simiristyl thiodipropionate (manufactured by Yoshitomi Pharmaceutical ■, trade name: DMTP r Yoshitomi), 0.3 part by weight of calcium stearate (manufactured by Sankyoki ■) as a higher fatty acid metal salt. Molecularly oriented fibers were obtained in the same manner as in Example 1, except that the above-mentioned measurements were carried out.

The results are shown in Table 1.

Comparative Example 1 Molecularly oriented fibers were obtained in the same manner as in Example 1, except that no organic thioether stabilizer was used, and the above measurements were performed.

The results are shown in Table 1.

From an ultra-high molecular weight polyethylene composition containing a surface stabilizer, molecularly oriented fibers with good tensile properties and less decrease in intrinsic viscosity [η] due to molding can be obtained.

Claims (1)

[Claims] 1) (A) 3 to 80% by weight of an ultra-high molecular weight polyolefin having an intrinsic viscosity [η] of 5 to 40 dl/g measured in a decalin solvent at 135°C; (B) a diluent: (C) Organic thioether stabilizer: 0.005 to 5 parts by weight based on 100 parts by weight of the total weight of (A) ultra-high molecular weight polyolefin and (B) diluent. Characteristic ultra-high molecular weight polyolefin composition. 2) (A) ultra-high molecular weight polyolefin having an intrinsic viscosity [η] of 5 to 40 dl/g measured in a decalin solvent at 135°C: 3 to 80% by weight; (B) a diluent: 97 to 20% by weight. , (C) organic thioether stabilizer: 0.005 to 5 parts by weight based on 100 parts by weight of the total weight of (A) ultra-high molecular weight polyolefin and (B) diluent; (D) metal salt of higher fatty acid: An ultra-high molecular weight polyolefin composition comprising 0.005 to 5 parts by weight based on 100 parts by weight of the total weight of (A) ultra-high molecular weight polyolefin and (B) diluent.