JPH06228388A - Powdered resin composition for powder molding - Google Patents

Abstract

PURPOSE:To provide an ionomer compsn. which can be easily powdered, exhibits excellent film-forming properties and release characteristics in powder molding such as rotational molding, gives a scratch-resistant molded article, and can substitute for polyvinyl chloride as a surfacing material of an automotive interior. CONSTITUTION:The compsn. comprises 100 pts.wt. ethylene-unsatd. carboxylic acid copolymer ionomer of which at least 5mol% of the unsatd. carboxylic acid units have been neutralized with metal ions and 1-20 pts.wt. polyoxyethylene glycol compd. and has a melt flow rate (190oC, 2160 g-load) of 1-100g/10min and a mean particle size of 1-500mum.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a powder of an ionomer composition used for powder molding such as rotational molding. More specifically, the present invention relates to a powder of an ionomer composition capable of easily manufacturing a powder and manufacturing 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 it has excellent moldability and grain transfer and can easily produce products with excellent aesthetics. Has been done. However, there are problems that corrosive gas is generated and specific gravity is relatively large when the waste material is incinerated, and the product weight is heavy, and there is a situation in which material conversion to a polyolefin type is required. Among them, particularly in the field where scratch resistance is required, an ionomer of an ethylene / unsaturated carboxylic acid copolymer, and in the field where further flexibility is required, an unsaturated carboxylic acid ester is contained as a copolymerization component. A possible alternative is an ionomer. However, in such an alternative, there are some problems to be solved in terms of molding and physical properties, and it is not easy to overcome them.

For example, in order to obtain ionomers for powder molding, fine powders have to be produced from ionomer pellets. However, since the ionomer has poor pulverizability, it is generally necessary to freeze-pulverize it, but it is still difficult to obtain an ionomer powder having a uniform particle size distribution. Also, in powder molding, fine warping may be performed for the purpose of decorating the skin of the molded product, but it is difficult to separate the molded product from the mold after the molding because the ionomer has excellent adhesiveness with metal. Was often the case.

[0004]

Therefore, the present inventors have found that
Studies were started to improve this defect by adding an additive to the ionomer. However, there are many problems in incorporating additives. That is, in general, ionomers are not easily pulverized by pulverization as described above, but pulverization tends to be more difficult when an additive is added. In addition, many additives give stickiness to the molded product. Therefore, in selecting the additive, not only the releasability is improved, but the pulverization is not adversely affected,
It is also an important factor that the molded product is not sticky. As a result of studying a number of additives from the above viewpoints, many generally known as mold release agents or slip agents for thermoplastic resins were not able to satisfy the above-mentioned desired performance. The present invention has been reached by discovering that only glycol-based compounds exhibit excellent performance.

Accordingly, it is an object of the present invention to provide a powdery ionomer composition suitable for powder molding which can be easily produced by mechanical grinding. Another object of the present invention is to
Provided is a powdery ionomer composition which has good film-forming property, grain transfer property, mold releasability and the like, and therefore has excellent aesthetics and which can easily be produced by powder molding. It is in. Still another object of the present invention is to provide a powdery 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 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 1 to 20 parts by weight of a polyoxyethylene glycol compound, the melt flow rate is 1 to 100 g / 10 minutes (190 ° C., 2160 g load), and the average particle diameter is 1 to 50.
A resin composition powder for powder molding having a diameter of 0 μm is provided.

The ionomer of the ethylene / unsaturated carboxylic acid copolymer used in the present invention may be copolymerized with another monomer such as an unsaturated ester as an optional polymerization component, and the unsaturated carboxylic acid polymerization is also possible. At least 5 mol% or more of the units have a structure neutralized with metal ions. If a low-neutralized or non-neutralized one is used, a composition having good release properties cannot be obtained even if the polyethylene glycol-based compound described below is added, and a molded product having excellent scratch resistance is obtained. It's difficult. Examples of the unsaturated carboxylic acid component include acrylic acid, methacrylic acid, monoethyl maleate, maleic anhydride and the like, and acrylic acid or methacrylic acid is particularly preferable.

Further, as another monomer which is an optional polymerization component, unsaturated ester, for example, vinyl ester such as vinyl acetate, or methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, acrylic is used. Examples thereof include unsaturated carboxylic acid esters such as 2-ethylhexyl acid, methyl methacrylate, and diethyl maleate.

Typical 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,
Ionomer neutralized with a divalent metal is preferable because the release effect can be obtained by using a small amount of a polyoxyethylene glycol compound.

The polymerization composition of the ethylene / unsaturated carboxylic acid copolymer is, for example, 50 to 98% by weight of ethylene,
The proportion of unsaturated carboxylic acid may be 2 to 35% by weight, and other monomer such as unsaturated ester may be 0 to 40% by weight. When a particularly flexible molded article is intended, 50 to 90% by weight of ethylene, especially 60 to 90% by weight, 2 to 30% by weight of unsaturated carboxylic acid, especially 5 to 20% by weight, unsaturated ester 5-30% by weight, especially 10-2
It is desirable to use 5% by weight.

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

Such an ionomer is obtained by a method of reacting the above-mentioned ethylene / unsaturated carboxylic acid copolymer obtained by high-pressure polymerization with a metal compound, or an ethylene / unsaturated carboxylic acid ester copolymer obtained by high-pressure polymerization. It can be produced by a saponification method or the like. In consideration of the film-forming property in powder molding, the ionomer is 190
Melt flow rate is 1g under 2160g load
/ 10 minutes or more, preferably 3 g / 10 minutes or more is preferably used. On the other hand, considering the pulverization characteristics of the ionomer and the physical properties of the molded product, the melt flow rate is 100 g /
It is preferable to use those for 10 minutes or less, particularly 50 g / 10 minutes or less.

In the present invention, a polyoxyethylene glycol-based compound, that is, polyoxyethylene glycol, an ether thereof, an ester thereof or the like is used as the ionomer. As the ether of polyoxyethylene glycol, alkyl ether, phenyl ether,
Examples of the alkyl phenyl ether and the like include polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan monostearate, and polyoxyethylene sorbitan monolaurate. Of these, the use of polyoxyethylene glycol is most effective. As the polyoxyethylene glycol-based compound, it can be widely used from a liquid form to a solid form at room temperature, for example, an average molecular weight of 200 to 50,
Although those having a molecular weight of about 4,000 can be used, it is preferable to use those having a molecular weight of about 400 to 20,000 in consideration of miscibility with an ionomer.

The preferable amount of the polyoxyethylene glycol compound to be blended varies depending on the kind of the ionomer, but if it is blended in too much, it will cause stickiness and deterioration of 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, these are melt-blended by a conventional method to produce pellets. It may then be mechanically ground. Since the ionomer does not have a high melting point, it is necessary to prevent the ionomer from being heated to a high temperature. For example, freeze pulverization is the most preferable method.
It should be noted that various additives such as an antioxidant, a weather resistance stabilizer, an ultraviolet absorber and a pigment may be blended in the blending of the above respective components. In the pulverization, the composition of the present invention can be performed with the same or higher efficiency as compared with the pulverization of the ionomer alone, and no particular drawback can be found by blending the polyoxyethylene glycol compound.

The blend thus obtained has a melt flow rate of 1 to 100 in consideration of film-forming properties and physical properties of molded products.
It is desirable to adjust to g / 10 minutes, particularly 3 to 50 g / 10 minutes. In consideration of moldability, surface appearance of the molded product, etc., the powder particle size is 1 to 500 μm,
Particularly, it is desirable to set the thickness in the range of 1 to 350 μm.

[0017]

EXAMPLES Next, examples and comparative examples will be shown. Examples,
The raw material resins and compounding agents used in the comparative examples, and the test methods carried out 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) Kanto Chemical Co., Ltd. reagent (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 wt% silicone ultra-high molecular weight polymer (viscosity 1 million cs or more 25 ° C.) / Low density polyethylene masterbatch) (b) Trefil F201 (high molecular weight) Dimethyl silicone oil 30000cs) (c) Trefil F202 (high molecular weight dimethyl silicone oil 60000cs) All manufactured by Toray Dow Corning Silicone Co., Ltd.

(6) Slip agent: (a) Erucic acid amide manufactured by Nippon Seika Co., Ltd. (b) N, N'-methylenebisstearic acid amide manufactured by Nippon Kasei (c) Glycerin monolauric acid Kanto Kagaku ( Co., Ltd. reagent

2. Test method (1) Production of resin composition pellets 30 nmφ twin-screw extruder (PCM30 manufactured by Ikegai Tekko KK)
3. The resin and additives are 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 Using an atomizer pulverizer, liquid nitrogen was used to cool the pellet resin to a temperature lower than the embrittlement temperature (about -150 ° C) and pulverize.

(3) Test method for film-forming property and mold releasability A preliminary test is carried out on pellets, and those having good film-forming properties and mold releasability are further tested on powder. It was For evaluation of pellets, a pellet-shaped test piece was placed on a hot press at 230 ° C., 10 g of pellet-shaped test pieces were placed thereon, left for 5 minutes, and immediately cooled with ice. The film-forming property was determined by the surface smoothness and the texture transfer property of the obtained sheet-shaped product, and the releasability was determined by manually peeling the sheet-shaped product from the mold. In addition, in the evaluation of powdery material, a die for transferring a grain pattern is preheated to 250 ° C., and the powder is placed on it and melted and held for 2 minutes. Then, the mold is tilted to remove unmelted powder, and then the mold is water-cooled. The film-formed molded article is similarly evaluated.

Judgment of film-forming property ◎ Smooth surface and good wrinkle transfer ○ Slight unevenness is observed on the surface, and wrinkle transfer is slightly insufficient.

Judgment of releasability ◎ Easy peeling by hand ○ Some force is required for peeling × No peeling

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

(5) Measurement of Melt Flow Rate 19 using a melt indexer (manufactured by Toyo Seiki Seisakusho)
It was measured at 0 ° C. and a load of 2160 g.

[Releasability and Film Forming Test from Pelletized Samples] Examples 1 to 8 Ionomer and polyoxyethylene glycol compound were blended in the composition shown in Table 1 to obtain pellets of the ionomer composition. The mold releasability and the film forming property were tested. The results are shown in Table 1.

[0038]

[Table 1] (*) POE: Polyoxyethylene glycol compound # 600, etc. are all polyoxyethylene glycol (numbers are average molecular weight) POESML: Polyoxyethylene sorbitan monolauric acid POESMP: Polyoxyethylene sorbitan monopalmitic acid

Comparative Examples 1 to 12 Mold releasability and film-forming properties were tested from pellets of an ionomer containing no polyoxyethylene glycol compound or a composition containing a silicone mold release agent, a slip agent and the like. . The results are shown in Table 2.

[0040]

[Table 2]

As is clear from the results shown in Tables 1 and 2, all the ionomer compositions containing the polyoxyethylene glycol-based compound have good mold releasability and film-forming property. It turns out that it is superior to the compounding recipe.

[Pulverization Test and Evaluation of Physical Properties of Molded Articles from Powder] The compositions of Example 3 and Comparative Example 3 were freeze-pulverized. The particle size and particle size distribution of the obtained powder are shown in Table 3.
It was as follows.

[0034]

[Table 3] However, IO: ionomer POEG: polyoxyethylene glycol

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

The powder thus obtained was tested for film-forming property and releasability, and the resulting molded product was evaluated for scratch resistance and heat deformation resistance. As a result, the composition of Example 3 was excellent in both film-forming property and releasability,
The molded product was not sticky.

The scratch resistance was the same in Examples 3 and 16. That is, the influence of the compounding of the polyoxyethylene glycol compound on other physical properties was not recognized.

[0038]

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an ionomer composition powder having excellent film-forming property 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 excellent flexibility and excellent scratch resistance.
Taking advantage of such characteristics, the powder of the present invention can be used for molding, for example, a skin of an automobile interior material, for example, an instrument panel safety pad, a plug door, a console skin, and the like.

Claims (1)

[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 with a metal ion, and polyoxyethylene glycol-based compounds 1 to 20.
The melt flow rate is 1 to 100 g.
/ 10 minutes (190 ° C., 2160 g load), resin composition powder for powder molding having an average particle diameter of 1 to 500 μm.