JP3342908B2 - Resin composition powder for powder molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ionomer composition powder used for powder molding such as rotational molding. More particularly, the present invention relates to an ionomer composition powder that can be easily produced and can produce a product having good scratch resistance with good moldability.

[0002]

2. Description of the Related Art Polyvinyl chloride is widely used as a skin material for various molded products because it is flexible and has excellent tactile sensation, and has good moldability and transferability, and can easily produce products with excellent appearance. Have been. However, there is a problem in that the generation of fouling gas and the specific gravity are relatively large at the time of incineration of waste materials, and the weight of products is heavy. Of these, especially in the field where scratch resistance is required, an ionomer of an ethylene / unsaturated carboxylic acid copolymer is contained, and in the field where further flexibility is required, an unsaturated carboxylic acid ester is contained as a copolymer component. Ionomer alternatives can be considered. However, in such an alternative, there are some problems to be solved in terms of molding or physical properties, and it has not been easy to overcome them.

[0003] For example, in order to obtain an ionomer for powder molding, a fine powder must be produced from ionomer pellets. However, since the pulverizability of the ionomer is poor, it is generally necessary to freeze-pulverize the powder, but it has been still difficult to obtain an ionomer powder having a uniform particle size distribution. Also, in powder molding, fine graining may be performed for the purpose of decorating the skin of the molded article, but it is difficult to remove the molded article from the graining mold after molding because the ionomer has excellent adhesion to metal Was often the case.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present inventors
Investigations have been started to improve this disadvantage by blending additives with the ionomer. However, there are many problems when formulating additives. That is, as described above, ionomers are generally not easily pulverized by pulverization, but pulverization tends to be more difficult when an additive is added. In addition, many additives give stickiness to molded articles. Therefore, the choice of additives not only improves the releasability, but does not adversely affect the pulverization,
An important factor is that it does not give the molded product stickiness. As a result of examining a large number of additives from the above viewpoints, many of those generally known as release agents or slip agents for thermoplastic resins could not satisfy the desired performance, but polyethylene. The inventors have found that only glycol compounds show excellent performance, and have reached the present invention.

Accordingly, an object of the present invention is to provide a powdered ionomer composition suitable for powder molding, which can be easily produced by mechanical pulverization. Another object of the present invention is to
Provided is a powdered ionomer composition which has good film-forming properties, grain transferability, releasability, etc., and is therefore excellent in aesthetic appearance, and which can easily produce a molded article excellent in scratch resistance by powder molding. It is in. Still another object of the present invention is to provide a powdered ionomer composition having the above-mentioned properties and capable of producing a molded article having improved heat resistance.

[0006]

That is, according to the present invention, 100% by weight of an ionomer of an ethylene / unsaturated carboxylic acid copolymer in which at least 5 mol% or more of unsaturated carboxylic acid polymerized units are neutralized by metal ions. And a polyoxyethylene glycol compound in an amount of 1 to 20 parts by weight, a melt flow rate of 1 to 100 g / 10 min (at 190 ° C. and a load of 2160 g), and an average particle size of 1 to 50.
A resin composition powder for powder molding having a thickness of 0 μm is provided.

[0007] The ionomer of the ethylene / unsaturated carboxylic acid copolymer used in the present invention may have another monomer such as an unsaturated ester copolymerized as an optional polymerization component. It has a structure in which at least 5 mol% or more of the units are neutralized with metal ions. When a low neutralization degree or a non-neutralization degree is used, a composition having good releasability cannot be obtained even when a polyethylene glycol compound described below is blended, and a molded article having excellent scratch resistance is obtained. It is difficult. Here, examples of the unsaturated carboxylic acid component include acrylic acid, methacrylic acid, monoethyl maleate, and maleic anhydride, and the use of acrylic acid or methacrylic acid is particularly preferable.

[0008] The other monomer which is an optional polymerization component may be an unsaturated ester, for example, a vinyl ester such as vinyl acetate, or methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, or acryl. Examples thereof include unsaturated carboxylic esters such as 2-ethylhexyl acid, methyl methacrylate, and diethyl maleate.

Representative examples of the metal ion species in the ionomer include monovalent metals such as lithium, sodium and potassium, and divalent metals such as zinc, magnesium and calcium. Among these,
An ionomer neutralized with a divalent metal is preferred because a small amount of a polyoxyethylene glycol-based compound has a releasing effect.

The polymerization composition of the ethylene / unsaturated carboxylic acid copolymer is, for example, 50 to 98% by weight of ethylene,
Unsaturated carboxylic acids may be in proportions from 2 to 35% by weight, and other monomers such as unsaturated esters may be in proportions from 0 to 40% by weight. When the purpose is particularly a flexible molded product, ethylene is 50 to 90% by weight, particularly 60 to 90% by weight, unsaturated carboxylic acid is 2 to 30% by weight, especially 5 to 20% by weight, and unsaturated ester is 5-30% by weight, especially 10-2
It is desirable to use 5% by weight.

Although the degree of neutralization by metal ions is 5 mol% or more, it tends to become harder as the degree of neutralization increases. Therefore, the degree of neutralization is preferably 80 mol% or less, particularly preferably 70 mol% or less.

[0012] Such an ionomer is prepared by a method of reacting the above-mentioned ethylene / unsaturated carboxylic acid copolymer obtained by high-pressure polymerization with a metal compound, or a method of producing an ethylene-unsaturated carboxylic acid ester copolymer obtained by high-pressure polymerization. It can be manufactured by a saponification method or the like. When the film forming property in powder molding is considered, the ionomer is slightly different depending on the molding temperature.
Melt flow rate at 2160g load is 1g
/ 10 min or more, preferably 3 g / 10 min or more is preferably used. On the other hand, in consideration of the pulverizing characteristics of the ionomer and the physical properties of the molded product, the melt flow rate is 100 g /
It is preferable to use one for 10 minutes or less, particularly 50 g / 10 minutes or less.

In the present invention, a polyoxyethylene glycol compound, that is, polyoxyethylene glycol, its ether, its ester, or the like is used as the ionomer. As ethers of polyoxyethylene glycol, alkyl ether, phenyl ether,
Examples of the alkyl phenyl ether and the like, and examples of the ester include polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan monostearate, and polyoxyethylene sorbitan monolaurate. Of these, the use of polyoxyethylene glycol is most effective. The polyoxyethylene glycol-based compound can be widely used from a liquid state to a solid state at room temperature, for example, having an average molecular weight of 200 to 50,
Although 000 can be used, it is preferable to use those having a molecular weight of about 400 to 20,000 in consideration of miscibility with the ionomer.

The preferred amount of the polyoxyethylene glycol compound varies depending on the type of the ionomer, but if it is used in an excessively large amount, it may cause stickiness or decrease in physical properties.
It is about 1 to 20 parts by weight, preferably about 2 to 15 parts by weight.

In order to produce a powder comprising an ionomer and a polyoxyethylene glycol compound, the powder is melt-blended by a conventional method to produce a pellet. Then, it may be mechanically pulverized. Since the ionomer does not have a high melting point, it is necessary to keep the temperature from being high during pulverization. For example, freeze pulverization is the most preferable method.
When blending the above components, various additives such as antioxidants, weather stabilizers, ultraviolet absorbers, pigments and the like can be blended. In the pulverization of the present invention, the pulverization can be carried out with the same or higher efficiency as compared with the pulverization of a single ionomer, and the drawbacks caused by blending the polyoxyethylene glycol-based compound are not particularly found.

The composition thus obtained has a melt flow rate of 1 to 100 in consideration of film forming properties and molded article properties.
g / 10 minutes, particularly preferably 3 to 50 g / 10 minutes. In addition, the powder particle diameter is 1 to 500 μm,
In particular, it is desirable to set it in the range of 1 to 350 μm.

[0017]

Next, examples and comparative examples will be described. Examples,
The raw material resins and compounding agents used in the comparative examples, the test methods performed, and the like are as follows.

1. Raw Materials Used (1) Copolymer A: Ethylene-methacrylic acid copolymer (methacrylic acid content 15% by weight, MFR 60 dg / mi
n)

(2) Copolymer B: ethylene-methacrylic acid-isobutyl acrylate terpolymer (methacrylic acid content 8% by weight, isobutyl acrylate content 20% by weight,
MFR 25dg / min)

(3) Saponified product: ethylene-ethyl acrylate copolymer (ethyl acrylate content 25% by weight, NF
R275 dg / min) 20 mol% with sodium
Saponified

(4) Polyoxyethylene glycol and its derivatives: (a) PEG # 600, # 1000, # 6000, # 10
000, # 20000 (numbers indicate average molecular weight) Reagents manufactured by Kanto Chemical Co., Ltd. (b) Polyoxyethylene sorbitan monolauric acid (H
LB16.7) manufactured by Kao Corporation (c) Polyoxyethylene sorbitan monopalmitic acid (HLB15.6) manufactured by Kao Corporation

(5) Silicone release agent: (a) BY27-002 (50% by weight silicone ultra-high molecular weight material (viscosity of 1,000,000 cs or more at 25 ° C.) / Low density polyethylene masterbatch) (b) Trefil F201 (high molecular weight) (Dimethyl silicone oil 30000 cs) (c) Trefil F202 (high molecular weight dimethyl silicone oil 60000 cs) Both manufactured by Dow Corning Toray Silicone Co., Ltd.

(6) Slip agent: (a) erucamide, manufactured by Nippon Seika Co., Ltd. (b) N, N'-methylenebisstearic acid amide manufactured by Nippon Kasei Co., Ltd. (c) glycerin monolaurate Kanto Chemical Co., Ltd. Co., Ltd. reagent

2. Test method (1) Production of resin composition pellets 30 nm φ twin screw extruder (PCM30 manufactured by Ikegai Iron Works Co., Ltd.)
The resin and additives were used at a resin temperature of 210 ° C. and an extrusion rate of 4.
It was extruded and pelletized at 0 kg / hr.

(2) Production of Resin Powder The resin in the form of pellets was cooled to below the embrittlement temperature (about -150 ° C.) using an atomizer pulverizer using liquid nitrogen and pulverized.

(3) Test Method for Film Forming and Releasability Preliminary tests were performed on pellets, and those with good film forming and releasability were also performed on powders. Was. The evaluation of the pellets was carried out by placing them in a mold for transferring a grain pattern on a hot press at 230 ° C., placing 10 g of the pellet-shaped test pieces, leaving them for 5 minutes, and immediately cooling them with ice. The film forming property was determined by the surface smoothness and the grain transferability of the obtained sheet, and the releasability was determined by peeling the sheet from the mold by hand. In the evaluation of the powdery material, the mold for transferring the grain pattern is heated to 250 ° C. in advance, and the powder is placed thereon and kept for 2 minutes to be melted and adhered. Thereafter, the mold is inclined to remove unmelted powder, and then the mold is water-cooled. The formed molded article is similarly evaluated.

Judgment of film-forming properties ◎ The surface is smooth and the grain transfer is good.

Judgment of releasability ◎ Peel easily by hand ○ Requires a little force to peel × No peel

(4) Scratch resistance test The surface of the molded article was scratched with a nail, and the scratched state was observed.

(5) Measurement of Melt Flow Rate Using a melt indexer (manufactured by Toyo Seiki Seisakusho), 19
It measured at 0 degreeC and 2160g load.

[Test of mold releasability and film forming property from pellet sample] Examples 1 to 8 The ionomer and the polyoxyethylene glycol compound were blended in the composition shown in Table 1, and the pellets of the obtained ionomer composition were used. , Release and film forming properties were tested. Table 1 shows the results.

[0038]

[Table 1] (*) POE: polyoxyethylene glycol compound # 600 etc. are all polyoxyethylene glycol (numbers are average molecular weight) POESML: polyoxyethylene sorbitan monolaurate POESMP: polyoxyethylene sorbitan monopalmitate

Comparative Examples 1 to 12 A test was conducted on the releasability and film forming property of an ionomer containing no polyoxyethylene glycol compound or a pellet containing a silicone release agent, a slip agent and the like. . Table 2 shows the results.

[0040]

[Table 2]

As is evident from the results in Tables 1 and 2, the ionomer compositions containing the polyoxyethylene glycol-based compound are all excellent in release properties and film-forming properties, and have a silicone release agent and a slip agent. It turns out that it is superior to the compounding formula.

[Pulverization Test and Evaluation of Physical Properties of Molded Article from Powder] The compositions of Example 3 and Comparative Example 3 were subjected to freeze-pulverization. Table 3 shows the particle size and particle size distribution of the obtained powder.
It was as follows.

[0034]

[Table 3] Where IO: Ionomer POEG: Polyoxyethylene glycol

The ionomer composition containing the polyoxyethylene glycol compound of Example 3 could be pulverized into a powder having a sufficiently small particle size, and there was no problem with the additives.

Further, a film forming property and a releasability test were carried out from the powder thus obtained, and the obtained molded product was evaluated for scratch resistance and heat deformation resistance. As a result, all the compositions of Example 3 had good film-forming properties and release properties,
There was no stickiness of the molded product.

The scratch resistance of Examples 3 and 16 was equivalent. That is, no influence on other physical properties due to the blending of the polyoxyethylene glycol compound was observed.

[0038]

According to the present invention, it is possible to provide an ionomer composition powder having excellent film forming properties and releasability in powder molding such as slush molding and rotational molding. The present invention can also provide an ionomer composition powder capable of producing a molded article having high flexibility and excellent scratch resistance.
Taking advantage of these features, the powder of the present invention can be used for molding, for example, the skin of automobile interior materials, for example, the skin of instrument panel safety pads, Bragg doors, consoles, and the like.

Claims (1)

(57) [Claims] 1. 100 parts by weight of an ionomer of an ethylene / unsaturated carboxylic acid copolymer in which at least 5 mol% or more of unsaturated carboxylic acid polymerized units are neutralized by metal ions, and polyoxyethylene glycol compounds 1 to 20
And 100 parts by weight of the melt flow rate
/ 10 minutes (190 ° C., 2160 g load), resin composition powder for powder molding having an average particle size of 1 to 500 μm.