JP2014189734A - Lubricant for cyclic olefinic thermoplastic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubricant for a cyclic olefinic thermoplastic resin good in heat resistance, and a cyclic olefinic thermoplastic resin composition having the lubricant, reducing stringiness during molding and excellent in transparency.SOLUTION: There is provided a lubricant for a cyclic olefinic thermoplastic resin consisting of ester A and ester B and having a mass ratio of the ester A and the ester B of 20:80 to 80:20. Ester A: castor hardened oil ester. Ester B: ester obtained from an aliphatic polyhydric alcohol having valence of 4 to 12 and a straight saturated aliphatic acid having 12 to 30 carbon atoms, and having the hydroxyl value of 25 mgKOH/g or less.

Description

  The present invention relates to a lubricant suitable for molding of a cyclic olefin-based thermoplastic resin and a cyclic olefin-based thermoplastic resin composition containing the lubricant.

  The thermoplastic resin is processed by various molding methods depending on the required shape by heating the resin to a temperature equal to or higher than the melting point or glass transition point. In particular, injection molding is widely performed because complicated shapes can be reproduced and mass production is possible. At this time, various additives are often added in order to improve the processability and stability of the resin. For example, in order to improve the lubricity of the resin and mold releasability, there is no lubricant depending on the application. About 0.01 to 10 parts by mass are added. As the lubricant, for example, as disclosed in Patent Document 1, paraffin wax, fatty acid ester, higher fatty acid, higher alcohol and the like are used.

  Among thermoplastic resins, cyclic olefin-based thermoplastic resins are attracting attention. Cyclic olefin-based thermoplastic resin is a thermoplastic resin having a cyclic olefin structure in the main chain, and has excellent properties such as transparency, heat resistance, chemical resistance, low water absorption, and low dielectric constant. Widely used in medical materials, electrical materials, etc. In particular, in recent years, optical materials such as in-vehicle cameras and imaging lenses for mobile phones have been desired to be reduced in size and weight, and the application of highly transparent cyclic olefin-based thermoplastic resins to these optical materials has become active. It has been broken.

However, cyclic olefin-based thermoplastic resins have a higher molding temperature than other thermoplastic resins, and various problems may occur when conventional lubricants for thermoplastic resins are used. For example, volatilization of the lubricant may cause contamination in the molding machine or change in the concentration of the lubricant in the resin. In addition, the cyclic olefin-based thermoplastic resin is likely to cause stringing during molding, and may cause defective products in which the yarn adheres to the molded product.
Various developments have been made to solve these problems. For example, Patent Document 2 shows that an ester such as 12-hydroxystearic acid triglyceride composed of an OH group-containing saturated fatty acid and an alcohol, or a saturated alcohol having 16 or more carbon atoms is used as a lubricant having high heat resistance. However, this lubricant may reduce the transparency of the resin molded product. In Patent Document 3, microcrystalline wax, pentaerythritol distearate, or the like having a 5 mass part reduction temperature in a nitrogen atmosphere of 300 ° C. or higher is shown as a lubricant having high heat resistance. However, when these lubricants are used, stringing is likely to occur during injection molding, resulting in molding defects and problems with heat resistance. Patent Document 4 shows that by using a branched resin or adding polyethylene, the shear viscosity and elongation viscosity of the resin can be adjusted to prevent stringing during molding. However, the heat resistance problem caused by lubricants such as pentaerythritol distearate has not been solved. Thus, for the development of a lubricant that improves the heat resistance of the lubricant itself, does not reduce the transparency of the cyclic olefin-based thermoplastic resin, and can suppress the occurrence of stringiness during injection molding. , Not yet reached.

JP 2005-187722 A JP-A-9-241484 JP 2008-208237 A JP 2010-82849 A

  The problem to be solved by the present invention is to provide a lubricant for a cyclic olefin thermoplastic resin having good heat resistance, and a cyclic olefin containing the lubricant, which has reduced stringiness during molding and is excellent in transparency. It is to provide a thermoplastic resin composition.

As a result of intensive research on lubricants suitable for blending with cyclic olefin-based thermoplastic resins that require high-temperature conditions during molding, the present inventors have found that lubricants combining specific types of esters themselves have high heat resistance. As a result, it was found that stringing during the molding of the cyclic olefin-based thermoplastic resin can be suppressed and transparency can be maintained, and the present invention has been completed.
That is, the present invention is as follows.
(1) A lubricant for cyclic olefin-based thermoplastic resins comprising ester A and ester B, wherein the mass ratio of ester A and ester B is 20:80 to 80:20.
Ester A: castor hydrogenated oil Ester B: ester (2) cyclic olefin obtained from aliphatic polyhydric alcohol having 4 to 12 valences and linear saturated fatty acid having 12 to 30 carbon atoms and having a hydroxyl value of 25 mgKOH / g or less The cyclic olefin type thermoplastic resin composition which contains 0.01-10 mass parts of said lubricants with respect to 100 mass parts of a thermoplastic resin.

  Since the lubricant of the present invention is hardly decomposed or volatilized even at a high temperature, it is particularly suitable as a lubricant for a cyclic olefin thermoplastic resin that requires a high molding temperature. In the cyclic olefin-based thermoplastic resin composition of the present invention containing the lubricant, stringing hardly occurs at the time of molding, and the transparency of the molded product is not impaired. Accordingly, the cyclic olefin-based thermoplastic resin composition is useful as a molding material for various products because it has good moldability and can fully utilize excellent transparency.

This will be described in more detail below.
<Ester A>
Ester A is castor oil and can be obtained by hydrogenating castor oil. Castor hydrogenated oil is an ester composed of a mixed fatty acid mainly composed of 12-hydroxystearic acid and glycerin.
The iodine value of ester A is preferably 5 or less, and more preferably 3 or less. An iodine value of 5 or less is preferable because coloring of the resin composition due to thermal deterioration during processing can be suppressed.
Castor hydrogenated oil satisfying the above conditions can be obtained as a commercial product, and examples thereof include castor wax A flake (manufactured by NOF Corporation), castor hydrogenated oil A (manufactured by Ito Oil Co., Ltd.) and the like. It is done.

<Ester B>
The ester B is an ester obtained from an aliphatic polyhydric alcohol having a valence of 4 to 12 and a linear saturated fatty acid having a carbon number of 12 to 30, and having a hydroxyl value of 25 mgKOH / g or less.
The aliphatic polyhydric alcohol is preferably a tetravalent to octavalent alcohol, more preferably a tetravalent alcohol. When the valence of the aliphatic polyhydric alcohol is 3 or less, deterioration of heat resistance and stringing occur, and when the valence is 13 or more, sufficient releasability is not exhibited.
Examples of the aliphatic polyhydric alcohol having a valence of 4 to 12 include pentaerythritol, dipentaerythritol, tripentaerythritol, diglycerin, triglycerin, tetraglycerin, pentaglycerin, hexaglycerin, heptaglycerin, octaglycerin, nonaglycerin, Examples include decaglycerin. In particular, pentaerythritol and dipentaerythritol are more preferable because of high heat resistance.

  The linear saturated fatty acid has 12 to 30 carbon atoms, preferably 18 to 22 carbon atoms. When the carbon number is 11 or less, since the melting point is low, the surface of the molded product is contaminated and the heat resistance is lowered. Moreover, the linear saturated fatty acid having 31 or more carbon atoms is difficult to obtain as an industrial product. Examples of the linear saturated fatty acid having 12 to 30 carbon atoms include lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, hexacosanoic acid, octacosanoic acid, triacontanoic acid and the like.

  The hydroxyl value of ester B is 25 mgKOH / g or less, preferably 10 mgKOH / g or less, more preferably 5 mgKOH / g or less. When the hydroxyl value is 25 mgKOH / g or more, the volatile content at high temperature is large, and stringing is likely to occur. The acid value is preferably 5 mgKOH / g or less, more preferably 3 mgKOH / g or less, and even more preferably 1 mgKOH / g or less. An acid value of 5 mgKOH / g or less is preferred because it has a low volatile content at high temperatures and high heat resistance.

Production methods of ester B include synthesis methods by oxidation reaction, synthesis from fatty acids and derivatives thereof, methods utilizing dehydration condensation reaction from fatty acids and alcohols, production methods such as reaction between acid halide and alcohol, transesterification reaction, etc. Is mentioned.
A catalyst may be used for the reaction, and examples of the catalyst include acidic or alkaline catalysts such as zinc acetate and titanium compounds. Both components used for the reaction are reacted in equimolar amounts, or one component is added in a large excess and reacted. Thereafter, it may be highly purified by a recrystallization method, a distillation method, a solvent extraction method, or the like.

<Lubricant>
In the lubricant of the present invention, the mass ratio of the ester A and the ester B is 20:80 to 80:20, preferably 30:70 to 50:50. If the mass ratio of the ester A is less than 20, a sufficient anti-threading effect cannot be obtained, and if the mass ratio of the ester A is higher than 80, the transparency is lowered and stringing is likely to occur during molding. Become.
The ester A and the ester B may be added separately, but are preferably added as a mixture prepared in advance. The mixing of the ester A and the ester B is preferably a method in which the ester A and the ester B are heated and melted at a temperature equal to or higher than the transparent melting point and uniformly mixed, then cooled and solidified, pulverized or granulated, A lubricant can be obtained.
The addition amount of the lubricant is preferably 0.01 to 3 parts by mass, more preferably 0.1 to 1 part by mass with respect to 100 parts by mass of the resin. When the amount of the lubricant used is 0.01 parts by mass or more, the release property is high, the stringing is reduced, and when it is 3 parts by mass or less, the heat resistance is high, which is preferable.

<Cyclic olefin thermoplastic resin>
The cyclic olefin-based thermoplastic resin is a thermoplastic resin composed of a homopolymer of a cyclic olefin monomer or a copolymer of a cyclic olefin monomer and ethylene, and a cyclic structure in the main chain or side chain of the resin. Have Examples of the cyclic olefin monomer include a single ring olefin such as cyclopentene and cyclohexene, a two ring olefin such as bicyclo [2.2.1] hept-2-ene, and tricyclo [4.3.0.1]. And tricyclic olefins such as deca-3,7-diene. Examples of the monomer that can be copolymerized with a cyclic olefin include α-olefins and styrenes.
As the cyclic olefin-based thermoplastic resin used in the present invention, commercially available products can be used. Product), APEL (manufactured by Mitsui Chemicals, Inc.) and the like can be used.

<Cyclic olefin-based thermoplastic resin composition>
The cyclic olefin-based thermoplastic resin composition of the present invention is obtained by blending the above-mentioned cyclic olefin-based thermoplastic resin with the lubricant of the present invention. Various additives may be added to the resin composition as long as the effects of the present invention are not affected. Specific examples of additives include, for example, fillers, pigments, thixotropic agents, antistatic agents, antifoaming agents, antioxidants, ultraviolet absorbers, light stabilizers, plasticizers, flame retardants and the like. It is done.

<Molding method>
The resin composition of the present invention can be used as a molding material in various known molding methods such as injection molding, extrusion molding, compression molding, blow molding, and vacuum molding.

EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited by a following example. In the following description, “part” means “part by mass” and “%” means “% by mass” unless otherwise specified.
Example 1
A four-necked flask equipped with a thermometer, a nitrogen inlet tube, an exhaust tube, and a stirring blade, castor castor oil (castor wax A flake, manufactured by NOF Corporation) (A-1), 40 parts, pentaerythritol tetrastearate (B-1) 60 parts were added, heated and melted at 100 ° C. under a nitrogen stream, mixed to be uniform, cooled and solidified, and pulverized to obtain a lubricant.
(Examples 2 to 10, Comparative Examples 1 to 12)
Using the ester A shown in Table 1 and the ester B shown in Table 2, the same operation as in Example 1 was performed to prepare a lubricant.

(Evaluation method of lubricant and resin composition)
(1) Heat resistance of the lubricant About the lubricant, using a differential thermothermal gravimetric simultaneous measurement device (EXSTAR TG / DTA6000 manufactured by SII NanoTechnology Co., Ltd.), a nitrogen flow rate of 200 ml / min, from 100 ° C. to 300 ° C. The temperature was raised under the conditions of ° C./min, and the weight reduction rate (mass%) after holding at 300 ° C. for 30 minutes was measured. The case where the weight reduction rate was 10% by mass or more was rated as x, the case where it was 5 or more and less than 10% by mass was marked as ◯, and the case where it was less than 5% by mass was marked as ◎. The results are shown in Table 3.

(2) Stringing property of resin composition 0.1 part of a lubricant is added to 100 parts of a cyclic olefin-based thermoplastic resin (TOPAS8007, MW80000 manufactured by Polyplastics Co., Ltd.), and melt-kneaded at 280 ° C for 2 minutes. Then, it was cooled and solidified, and pulverized to obtain a resin composition. The resin composition is softened by placing it on a hot plate heated to 150 ° C., and a cylindrical probe with a flat tip having a diameter of 12 mm is brought into contact with the resin composition until the distance between the hot plate and the probe tip becomes 0.3 mm. Crushed. Next, the resin composition protruding from the probe tip was scraped off to form a softened resin composition having a diameter of 12 mm and a height of 0.3 mm between the hot plate and the probe tip. The probe was pulled up 10 cm at 10 cm / second, and the length (cm) of the yarn of the resin composition cut from the hot plate and pulled from the probe tip was measured. The results are shown in Table 3.

(3) Transparency of resin composition 1.5 parts of a lubricant was added to 100 parts of a cyclic olefin-based thermoplastic resin (TOPAS 8007, MW 80000 manufactured by Polyplastics Co., Ltd.), and melt-kneaded at 280 ° C for 2 minutes. Next, it was poured into a cylindrical aluminum cup having a radius of 55 mm, and cooled and solidified to obtain a cylindrical resin composition having a thickness of 5.0 mm and a radius of 55 mm. The total light transmittance (%) of the resin composition was measured according to JIS K7105 using a haze meter (NDH-5000 manufactured by Nippon Denshoku Industries Co., Ltd.). The results are shown in Table 3.

As a reference example, the stringiness and transparency of a resin composition not containing a lubricant were evaluated. The examples and comparative examples were evaluated based on the stringiness and transparency of the reference example.
The lubricants of Examples 1 to 10 showed high heat resistance, and the resin compositions using the lubricants of Examples 1 to 10 showed high transparency with suppressed stringing.
On the other hand, in Comparative Example 1 using only A-1 as a lubricant, the transparency of the resin composition was low and the stringiness was high.
In the lubricant of Comparative Example 2 consisting of 85 parts A-1 and 15 parts B-1, the resin composition had low transparency and high stringiness.
In the lubricant of Comparative Example 3 consisting of 15 parts A-1 and 85 parts B-1, the stringiness of the resin composition was high.
In Comparative Example 4 using only B-1 as a lubricant, the resin composition had high stringiness.
In Comparative Example 5 using A-2 instead of A-1 in Example 1, the stringiness of the resin composition was high.
In Comparative Example 6 in which A-3 was used instead of A-1 in Example 1, the heat resistance was low and the stringiness of the resin composition was high.
In Comparative Example 7 in which A-4 was used instead of A-1 in Example 1, the heat resistance was low and the stringiness of the resin composition was high.
In Comparative Example 8 using only A-4 as a lubricant, the heat resistance was low, and the stringiness of the resin composition was high.
In Example 1, instead of B-1, Comparative Example 9 using B-9 having a fatty acid chain length of 9 had low heat resistance and high stringiness of the resin composition.
In Example 1, instead of B-1, in Comparative Example 10 using B-10 which is a monovalent ester, the heat resistance was low and the stringiness of the resin composition was high.
In Comparative Example 11 using B-11 which is a trivalent ester instead of B-1 in Example 1, the stringiness of the resin composition was high.
In Example 1, instead of B-1, in Comparative Example 12 using pentaerythritol triester B-12, the heat resistance was low and the stringiness of the resin composition was high.

Claims (2)

A lubricant for cyclic olefin-based thermoplastic resins, which comprises ester A and ester B, and the mass ratio of ester A and ester B is 20:80 to 80:20.
Ester A: castor hydrogenated oil Ester B: an ester obtained from an aliphatic polyhydric alcohol having a valence of 4 to 12 and a linear saturated fatty acid having a carbon number of 12 to 30 and having a hydroxyl value of 25 mgKOH / g or less The cyclic olefin type thermoplastic resin composition which contains 0.01-10 mass parts of lubricants of Claim 1 with respect to 100 mass parts of cyclic olefin type thermoplastic resins.