JPH0477528A - Coloring master-batch resin composition free from mold-deposition property - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is a method of mixing a mold deposit-preventing colored masterbatch resin composition with a polyacetal resin to prevent the formation of mold deposits in the mold during injection molding, casting molding, etc. Significantly suppresses the formation of precipitates, so-called mold deposits,
This invention relates to a colored master hatch resin composition that improves the productivity of molded products.

[Prior Art] In recent years, polyacetal resin has been widely used in many fields such as electrical parts, office equipment parts, and building materials because it has excellent strength, fatigue, and electrical properties, and its demand is increasing year by year. It is increasing.

In addition, polyacetal resins that are used in a wide variety of appearance applications and that are colored in various colors by adding colorants are in great demand, as are general colorless polyacetal resins.

Conventionally, colored polyacetal resins have been produced by adding a coloring agent to polyacetal resin powder or pellets and kneading them using an extruder, and by adding a large amount of coloring agent to thermoplastic resin in advance. There are two main methods: producing a highly concentrated colored polyacetal resin masterbatch using an extruder, kneading mixer, etc., blending this colored masterbatch with polyacetal resin, uniformly blending it, and obtaining the desired colored product by injection molding or extrusion molding. It has been adopted.

This colored polyacetal resin is usually molded into the desired shape by injection molding, or at this time, a so-called mold deposit is generated on the surface of the mold, and as a result of being transferred to the surface of the molded product, the appearance of the molded product is significantly affected. The disadvantage is that it is difficult to use as a material for parts that require high dimensional accuracy, such as gears, because the dimensional accuracy decreases.

In order to minimize such troubles, the molds used for molding polyacetal resin must be disassembled and cleaned every time they are used, but this takes a lot of time, so it is difficult to avoid reducing productivity. do not have.

By the way, in order to improve the thermal stability of polyacetal resin, it has been proposed to blend polyamide resin into it (Japanese Patent Publication No. 34-5440), but in the case of Kono, heat and oxygen are not released in the cylinder of the molding machine. This causes problems such as discoloration to yellow-brown and black-brown burnt or adhering to the screw. Additionally, boric acid ester of monoacylglycerin has been blended with polyacetal resin for the purpose of imparting an anti-electrification effect without impairing its thermal stability (Japanese Patent Publication No. 15616/1983); Colored polyacetal resins to which 8 additives were added alone were not necessarily satisfactory in terms of preventing mold deposits.

[Problems to be Solved by the Invention] The present invention significantly suppresses mold deposits that occur in the mold when molding colored polyacetal resin using a mold such as injection molding or casting molding, and improves the quality of the molded product. Excellent thermal stability that can improve productivity.
This was made for the purpose of providing a colored masterbatch resin composition for polyacetal resin.

[Means for solving the problem] The present inventors used a colored masterbatch resin composition,
As a result of intensive research in order to prevent the formation of mold deposits that adhere to the inside of the mold when molding colored polyacetal resin, we have found that polyamide resin 0.001 x D weight parts to 0.5 parts by weight per 100 weight parts of thermoplastic resin. A colored masterbatch resin composition containing xD parts by weight, 0.0I x D to 5 x D weight parts of a boric acid ester of monoacylglycerin, and a colorant (pigment) in any proportion can achieve its purpose. We have discovered what can be achieved and have completed the present invention. D here represents the dilution ratio of the masterbatch,
The dilution ratio refers to the ratio of the colored masterbatch resin composition to the uncolored polyacetal resin, for example, 2.
0 times dilution means colored masterbatch:polyacetal resin=1:19 (weight ratio). D is preferably 2-
It is 100 times more.

The thermoplastic resin used as component (A) in the composition of the present invention includes, for example, polyacetal resin, polyester resin, polyamide resin, polycarbonate resin, polyolefin resin, polyphenylene oxide resin, polystyrene resin, ABS resin, AS resin, acrylic resin, etc. Although they may be used alone or in combination, polyacetal resin alone is particularly preferred.

In the composition of the present invention, the polyamide resin used as component (B) is a linear polymeric compound having an acid amide bond -CONH-, and is usually formed by condensation of diamine and dicarboxylic acid, condensation of amino acid, or lactam. It can be obtained by ring-opening polymerization etc. Examples of the polyamide resin include nylon 6, nylon 6.6, nylon 6/6.6, nylon 6/6.10, nylon 6.6/6.10, nylon 6.10, nylon 6/6.6/ 6/10, nylon 12, etc. Among these polyamide resins, nylon 6/6, nylon 6/6/6, nylon 6
- 6/6.10 and nylon 6/6.6/6.10 are suitable.

These polyamide resins may be used alone or in combination of two or more, and the blending amount is as follows:
(A) 0.001× for 100 parts by weight of thermoplastic resin
D~0.5*D weight parts, preferably 0.05*D~0.
It is necessary to select within the range of 5×D weight parts. If this amount is less than 0.001 x Dii weight parts, the mold deposit prevention effect will not be sufficiently exhibited, and if it exceeds 0.05 x D weight parts, the color will turn brown due to the action of heat and oxygen in the molding machine cylinder over time. or a blackish brown mark may appear on the screw.

The boric acid ester of monoacylglycerin as component (C) in the composition of the present invention may be obtained by reacting, for example, a monoester of a fatty acid having 8 to 22 carbon atoms with glycerin and boric acid. R3 in the middle has 7 to 21 carbon atoms
or an alkyl group or an alkenyl group, m is 1 or 2) as a main component. Specific examples of the fatty acids include capric acid, lauric acid, myristic acid, stearic acid, linoleic acid, oleic acid, and hehenic acid. This boric acid ester may be either a monoester or a diester.

The boric acid ester of monoacylglycerin as component (C) may be used alone or in combination of two or more. The blending amount is 0.01 x D to 5 x per 100 parts by weight of the polyacetal resin of the component (A).
It is necessary to select parts by weight of D, preferably in the range of O, 0I×D to 3×D by weight. If this amount is less than 0.01 x D parts by weight, the mold deposit preventing effect due to the synergistic effect with the polyamide resin will not be sufficiently exhibited, and if it exceeds 5 x D parts by weight, the polyacetal resin will be easily thermally decomposed.

Furthermore, the coloring agent refers to generally-known organic pigments and inorganic pigments, and also includes treated pigments that have been imparted with dispersibility, heat resistance, weather resistance, etc.

Further, the amount of coloring agent added is not particularly limited, and is added in a necessary amount depending on the dilution ratio.

The polyacetal resin may be a polyacetal homopolymer or a polyacetal copolymer. The polyacetal homopolymer is composed of repeating oxymethylene units of 1,000 CH2O←, and can be produced by homopolymerizing formaldehyde or trioxane.

On the other hand, a polyacetal copolymer has a general formula (in which R' and R2 are each a hydrogen atom, an alkyl group, or an aryl group, and adjacent R1s and adjacent R2 , and R' and R2 may be the same or different, and n is an integer of 2 to 6) having a structure in which oxyalkylene units are randomly introduced. It is.

The content of the oxyalkylene units in this copolymer is 0.05 per 100 moles of oxymethylene units.
-50 mol, preferably 0.1-20 mol. Examples of the oxyalkylene units include oxyethylene units, oxypropylene units, oxytrimethylene units, oxytetramethylene units, oxybutylene units, and oxyphenylethylene units. Among these oxyalkylene units, oxyethylene units/(CHz)jo+- and oxytetramethylene units/(CH2)40+- are particularly preferred from the viewpoint of improving the physical properties of the polyacetal resin composition.

The polyacetal copolymer can be produced, for example, by copolymerizing a cyclic ether and at least one selected from formaldehyde, trioxane, and polyoxymethylene.

As a criterion for the ability to prevent mold deposits, the resin composition of the present invention is uniformly blended with polyacetal resin in any proportion, and continuous molding is performed, and in addition to visual judgment of precipitates that adhere to the mold surface, there is also the amount of pyrolytic volatile content. The thermal decomposition volatile content of the molded piece after the blending is usually 1500 ppm or less.

If desired, the masterbatch resin composition of the present invention may contain other heat stabilizers such as amide compounds, urea conductors, polysaccharides, cellulose, etc., to the extent that the object of the present invention is not impaired.
Alternatively, antioxidants, light stabilizers, lubricants, etc. with low decomposition effects may be added to the polyacetal resin, or low molecular weight polymers such as polyolefin waxes may be added as colorant dispersion improvers. good.

[Example] Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited in any way by these examples.

In addition, the characteristics of the colored polyacetal resin composition composed of a colored masterbatch resin composition and a polyacetal resin were determined according to the following method.

(1) Mold deposit (MD) and burn-on occurrence Using an injection molding machine, a molded product with a length of 75 mm, width of 14 mm, and thickness of 2 mm is continuously injection molded at a cylinder temperature of 200°C and a mold temperature of 70°C. In this operation, using a pin gate mold (without waste removal), determine the number of moldings until the surface of the molded product starts to lose its luster from the occurrence of all MD, and the number of days until a slight burn occurs on the surface of the molding machine screw. evaluated.

(2) Generation of silver streaks Using an injection molding machine, the composition was allowed to stay at a cylinder temperature of 230°C, and the critical residence time at which silver streaks due to decomposed formaldehyde gas would occur on the molded product was determined and evaluated.

(3) Pyrolysis volatile content: Place 10 g of the sample (molded piece) into a cylindrical stainless steel container with an inner diameter of 50 mm and a depth of 50 mm, place a stainless steel lid on top, seal it, and store it in a silicone container at 200°C. After 180 minutes of immersion in an oil bath, the amount of volatile matter adhering to the stainless steel jacket was determined, and the amount of pyrolysis volatile matter [ppm (W/W)] was determined.

Note that cooling water at 25° C. is passed through the upper lid to prevent volatilization and adhesion.

Examples 1 to 10, Comparative Examples 1 to 6 Polyacetal resin copolymer [MI=9.0g/10
(190°C) per 100 parts by weight of thermoplastic resin (polyacetal resin copolymer) into a mixture of 100 parts by weight of copolymer and 3 parts by weight of 2°2'-methylenebis(4-methyl-6-t-butylphenol). , Nylon in the proportions shown in Table 1: /6/6・8/6・10 (weight ratio 80/2
0/20) Ternary copolymerized polyamide resin and boric acid ester of monolauryl glycerin, and carbon black as a coloring agent...4 parts by weight (ethylene F black/BAS
Table 1 shows the results of blending and evaluating the properties of a masterbatch resin composition consisting of a blend of a masterbatch resin composition (manufactured by Company F). In addition, the MI values listed in Tables 1 to 4 are AST
This is a value measured under M standard D1Z38-E conditions.

As shown in Table 1, in the masterbatch for 20-fold dilution, component B (polyamide resin) is used for thermoplastic resin.
If the content exceeds 10 parts by weight (0,5
If it is less than 20), the effect of preventing MD occurrence will be lost.

In addition, if the C component (boric acid monoester of monolauryl glycerin) is less than 0.2 parts by weight (0.0IX20), M
There is no D-preventing effect, and if it exceeds 100 parts by weight (5 x 20), the thermal stability will be greatly reduced, the time for silver streaks to occur will be accelerated, and the amount of pyrolytic volatile matter will also be greatly increased.

Examples 11 to 17 A masterbatch resin composition was prepared in the same manner as in Example 1, except that the type of component B (polyamide resin) was changed and boric acid monoester of monostearylglycerin was used as component C, and a polyacetal resin copolymer and The blend was mixed and its properties were determined and evaluated.

The results are shown in Table 2.

Comparative Example 7 A test was carried out in the same manner as in Example 11 using a masterbatch resin composition to which no polyamide resin or boric acid ester of monoacylglycerin was added.

The results are shown in Table 2.

Examples 18 to 25 Homopolymer [MI=24
．． 0g/10 minutes (190°C)] and the same method as in Example 1 was performed except that the polyamide resin of the type shown in Table 3 and the boric acid monoester of monobehenylglycerin were used as the C component.

Comparative Example 8 Table 3 shows the results of the same procedure as Comparative Example 7 except that a homopolymer [MI=24.0 g/10 min (190° C.)] was used as the polyacetal resin.

As can be seen from Tables 2 and 3, the synergistic effect of the polyamide resin and the boric acid ester of monoacylglycerin significantly prevents all MD occurrences, increases the number of days for burnt occurrence and the time for silver streak occurrence, and The amount of decomposed volatile matter is also significantly reduced compared to the product to which polyamide resin and monoacylglycerin boric acid ester are not added.

These phenomena are the same whether the polyacetal resin is a copolymer or a homopolymer.

Examples 26 to 29 Thermoplastic resin (polyacetal resin copolymer) and polyamide resin (nylon 6/6/6/
6.10) and boric acid monoester of monolaurylglycerin, and the masterbatch dilution ratio was 10.40.
A masterbatch resin composition was prepared and evaluated in the same manner as in Example 1.

Also, as the thermoplastic resin, low density polyethylene (LDPE) was used instead of the polyacetal resin copolymer of Example 3.
...Product was carried out in the same manner as in Example 3 except that Ace Polyethylene M6525 (trade name) manufactured by Ace Polyethylene (trade name) was used.

The results are shown in Table 4.

As shown in Table 4, dilute the masterbatch by 1.
Even when the magnification is 0.40.60, the occurrence of MD is prevented as in Example 3, and MD is prevented even when LDPE is used as the thermoplastic resin.
Light generation is prevented, the number of days for scorch occurrence and the time for silver streaks to occur are lengthened, and the amount of pyrolysis volatile matter is also reduced.

[Effects of the Invention] According to the present invention, a colored masterbatch for polyacetal resin, which is a thermoplastic resin, a polyamide resin, a boric acid ester of glycerin 1,000 fatty acid ester, and a coloring agent, is blended with a polyacetal resin to produce a colored polyacetal resin. When producing products, the formation of mold deposits that adhere to the inside of the mold during molding such as injection molding can be significantly suppressed, making it possible to improve the productivity of molded products. Moreover, it is possible to easily obtain a polyacetal resin composition that has excellent thermal stability and is less likely to stick to the screw.

Claims (1)

Scope of Claims: (A) 100 parts by weight of thermoplastic resin, (B) 0.001 to 0.5 parts by weight of polyamide resin, and (C) 0.0 to 0.5 parts by weight of monoacylglycerin boric acid ester. 01
A mold deposit-preventing colored masterbatch resin composition for polyacetal resin, which is comprised of xD weight parts to 5 x D weight parts (D: represents the dilution ratio of the masterbatch) and a colorant.