JPH01245070A - Foam coating resin powder composition for metal and production thereof - Google Patents

Abstract

PURPOSE:To obtain the title composition suitable for imparting metallic wires and plates with thermal insulation, sweating proofness and buffer, by incorporating a specific polyethylene resin with an organic peroxide and a foaming agent followed by kneading under specified conditions and by grinding the resultant product. CONSTITUTION:A blend comprising (A) 100pts.wt. of (i) an ethylene-vinyl acetate copolymer with a melt index of 4-60 or (ii) polyethylene with a long chain branching degree of the polymer chain and number of terminal methyl group of 3-18 per 10<3> carbon atoms, (B) 0.2-3.0pts.wt. of an organic peroxide with an one-hour half life temperature of 105-160 deg.C (e.g., dicumyl peroxide), and (C) 0.5-10pts.wt. of a foaming agent having a decomposition temperature higher than that of the component B is kneaded while keeping the temperature higher than the melting point of the component A bat lower than the decomposition temperature of the component B followed by grinding the resultant product, thus obtaining the objective composition.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a resin powder composition for foam coating on metal surfaces, and more particularly, it relates to a resin powder composition for foam coating on metal surfaces. The present invention relates to a crosslinked foamable coating resin powder composition suitable for imparting heat insulation, anti-condensation, buffering, vibration-proofing, sound-insulating properties, etc.

(Conventional technology) Compared to conventional solvent coating, coating with polyethylene resin powder does not use dangerous solvents, has high coating efficiency, can be coated with a thick film at -degrees, and has sharp edges. It is widely used as an anti-corrosion coating for racks for plates and bottles, bicycles, aquaculture cages, fences, and pipes because it has excellent corrosion resistance, is durable, is inexpensive, and can be coated easily. .

In recent years, foam coatings have been attracting attention as a means to improve corrosion resistance by increasing adhesion to metals and to provide functions such as heat insulation to metal surfaces (Japanese Patent Application Laid-open No. 7379/1983).

In addition, various resin foam coatings have recently been studied as a method of eliminating the sound of metal pressing and metal contact that occurs between the frame line of an automobile seat and a spring spring.

For example, a method using vinyl chloride foaming paste, a method using polyurethane foaming based on a chemical reaction between a polyester or polyether type prepolymer having hydroxyl groups and incyanate, and a powder composition in which an organic decomposable blowing agent is added to a polyethylene resin. There is a known method (Japanese Patent Publication No. 53-21896) in which a foamed film is applied by applying it to a metal surface that has been preheated to a high temperature and then heating it at 100 to 300° C. for less than 10 minutes.

(Problems to be Solved by the Invention) However, the method using vinyl chloride foam paste requires special pretreatment of the metal surface in order to maintain adhesion to the metal. The problem with the urethane foaming method is that in order to perform foaming smoothly and uniformly, working conditions and environmental conditions must be controlled within as narrow a range as possible, and it takes a long time to complete foaming. have. The method disclosed in Japanese Patent Publication No. 53-21896 requires a very narrow range of coating conditions to achieve a foam coating with a uniform and fine foam cell structure and high closed-cell properties, which is the greatest feature of foam layers, and the quality is stable. At present, it is not possible to obtain a foamed film with a high quality.

The present applicant had previously proposed a powder polyethylene composition for cross-linking and foaming containing a polyethylene resin as a main component as a composition for carpet backing.
1) We have completed a technology for backing carpets by increasing the uniformity and closed cell nature of the foam cell structure and achieving a high expansion ratio.

In order to solve the above-mentioned drawbacks of the conventional products, the present inventors conducted further intensive research into powder polyethylene compositions for cross-linking and foaming, especially regarding the problem of stabilizing the quality of foam coatings. The present inventors have discovered that a stabilized crosslinked foam coating can be easily obtained by using a resin, and have completed the present invention.

(Means and Effects for Solving the Problems) The present invention provides (1) an ethylene-vinyl acetate copolymer having a melt index in the range of 4 to 60, or a long chain branching degree of the polymer chain and a terminal methyl group per 103 carbon atoms. 100 parts by weight of polyethylene containing 3 or more polyethylenes and 18 or more polyethylenes, 0.2 to 3.0 parts by weight of an organic peroxide having a one-hour half-life temperature in the range of 105°C or more and 160°C or less, and the organic peroxide. 0.5 to 10 parts by weight of a blowing agent with a decomposition temperature equal to or higher than that of the foam, and with a particle size of 5.
Resin powder composition for foam coating on metal (2) characterized by having a melt index of 4 or more and 60 or less, or an ethylene vinyl acetate copolymer having a melt index in the range of 4 or more and 60 or less, or a long chain branching degree of the polymer chain and 100 parts by weight of polyethylene having 3 or more terminal methyl groups and 18 or more terminal methyl groups per 103 carbon atoms, respectively, and 0.2 to 3.0 parts of an organic peroxide having a one-hour half-life temperature in the range of 105°C to 160°C. parts by weight and 0.5 to 10 parts by weight of a blowing agent having a decomposition temperature equivalent to or higher than that of the organic peroxide, and the melting point of the ethylene-vinyl acetate copolymer or polyethylene is mixed,
Provided is a method for producing a resin powder composition for foam coating on metal, which comprises kneading the composition while maintaining the temperature below the decomposition temperature of the organic peroxide, and then pulverizing the composition to a particle size of 500 μm or less.

By using the resin powder composition of the present invention, the range of foam coating processing conditions is widened, and a foam coating film with uniform, fine, and highly closed-cell properties can be easily obtained. What is important in the present invention is that the polyethylene resin is an ethylene vinyl acetate copolymer with high crosslinking reactivity with organic peroxides or polyethylene having a specific degree of long chain branching and a terminal methyl group; Regarding the relationship between the decomposition temperature of the organic peroxide blended into the resin and the blowing agent, it is important that the organic peroxide has a decomposition temperature equal to or lower than the blowing agent.

That is, the organic peroxide decomposes prior to the decomposition of the foaming agent, creating chemical bonds between polyethylene molecules and providing a melt viscosity suitable for foaming.

The base resin used in the present invention has a melt index (hereinafter referred to as MI) in the range of 4 to 60 (JIS
The long chain branching degree of the ethylene vinyl acetate copolymer or polymer chain (measured according to K6760) and the terminal methyl group per 103 carbon atoms are 3 or more and 18, respectively.
d polyethylene (preferably with a density of 0.91
~0.9397 cm3).

In addition, the polyethylene referred to in the present invention may be an ethylene copolymer, such as ethylene vinyl acetate (EVA), ethylene-ethyl acrylate (ERA), ethylene-acrylic 1 (EAA), or ethylene-methyl, if necessary. A material containing 50% or less of one or more of acrylate (EMA), a copolymer, or an ionomer resin can also be suitably used. Polyethylene and BVA when polyethylene alone has low elasticity
, ERA, EMA, etc. can be used to provide appropriate buffering properties. When strong adhesion to metal is required, a blend system with FAA or ionomer resin is preferably used. If the MI is less than 4, the melt fluidity is low and the coating film has an appearance with poor smoothness, which is not preferable. If the MI exceeds 60, the fluidity during melting will be too high and the foamed cells will be non-uniform, making it impossible to obtain a good foamed coating.

The degree of long chain branching of polyethylene polymer chains is reported in “Molecular Design of Polymers I (Fundamentals of Molecular Design)” published by Watama Baifukan Co., Ltd., pages 109-130 of “Viscosity and GP
(Hereinafter, in the present invention, the degree of long chain branching is referred to as LOB.) The degree of branching of polyethylene is determined by A, H, Wlllbou.
rn, J@Polymer Sci,, 34.
569 (1959), expressed by the number of terminal methyl groups per 103 carbon atoms of the polyethylene chain, and according to the method specified in ASTM D2238, 1378 crn-tortoise.

It is measured from the infrared absorption intensity of 1303 cm-''.

As described above, ethylene vinyl acetate copolymer or polyethylene having a high degree of long chain branching and a large number of terminal methyl groups has particularly high crosslinking reactivity with organic peroxides, and the foaming properties during foam coating processing are greatly improved.

That is, since the polyethylene resin is efficiently crosslinked prior to the decomposition of the blowing agent, the melt viscoelasticity of the resin is high, uniform fine closed cells are generated, and the effective utilization rate of the blowing agent is high. Enables coating with high expansion ratio.

The organic peroxide used in the present invention acts to increase the melt viscosity of the resin to provide film strength to the foamed cells during foaming, and has a half-life of 105°C or more and 160°C per hour.
Use the following items. If this temperature is less than 105°C, the crosslinking reaction will occur too quickly during coating processing, and not only will a good appearance of the foamed film not be obtained, but also premature crosslinking will occur during heating and kneading during the production of this composition, which is undesirable. .

On the other hand, if the temperature exceeds 160°C, the foaming agent decomposes before crosslinking, and the membrane strength of the foamed cells becomes insufficient, resulting in a uniform foamed hill,
A foam coating with high closed cell properties cannot be obtained. Preferred organic peroxides have a half-life temperature of 115°C to 1 hour.
The temperature range is 50°C. Specific examples include Cucumyl A-oxide (137°C), 1,3-bis(tert-butylperoxyisopropyl)benzene (141°C),
2,5-dimethyl-2,5-di(tert-butylperoxy)hexane (138°C), 2,5-dimethyl-
Although organic 1,3-bis(tertiarybutyl) does not leave any unpleasant odor in the residue of peroxide decomposition.
oxyisopropyl)benzene is preferred. The number in parentheses is the temperature at which the half-reduced group lasts for 1 hour, hereinafter referred to as the decomposition temperature.

The amount of organic peroxide blended varies depending on the individual activity, but is usually 0.2 to 3.0 parts by weight, preferably 0.5 to 1.5 parts by weight, per 100 parts by weight of the base resin. selected within the range. If the amount is less than 0.2 parts by weight, the degree of crosslinking will be insufficient, the melt viscosity during foam coating will be low, and the foam cells will become coarse, which is not compatible with the present invention.

On the other hand, if it exceeds 3 parts by weight, the amount will be more than necessary, it will be uneconomical, the melt viscosity will be too high, and the fluidity of the resin will be significantly inhibited, which will impede foaming.

The blowing agent used in the present invention is a decomposable organic blowing agent that decomposes upon heating and generates gas. The decomposition temperature is equivalent to or higher than that of the organic peroxide used in the present invention, and is preferably in the range of 120 to 210°C. The preferred particle size of the blowing agent is 50μ.
Use the following items.

If the particle size of the foaming agent exceeds 50 μm, large bubbles may be generated locally, which may tend to result in non-uniform foaming. In this case, the appearance of the foamed coating will be poor. Foaming agent powder generally has a distribution in particle size, but the particle size in the present invention is expressed as the median value (representative value) of the particle size range that occupies the largest proportion by weight of the entire powder. It is. The particle size can be easily measured using a particle size distribution measuring device using a commercially available sedimentation method.

Specific examples of blowing agents include azodicarzenamide (20
0-210°C), 4,4'-oxybisbenzenesulfonyl hydrazide (155-160°C), dinitrone pentamethylenetetramine (200-205°C), etc.; , one whose decomposition temperature is adjusted to 150 to 200°C is suitable. ()
The numbers inside indicate the decomposition temperature, which is 2°C/2°C in liquid paraffin.
It is defined as the temperature at which the most violent decomposition gas is generated when the temperature is increased at a rate of 100 min.

If the decomposition temperature is lower than 120° C., the composition of the present invention will foam when kneaded with an extruder, which is not only undesirable but also makes it impossible to obtain uniform foam cells during foam coating.

A decomposition temperature higher than 210°C is undesirable because it takes a long time for crosslinking and foaming. The most preferable decomposition temperature is 150-2
It is in the range of 00°C.

Examples of foaming aids include metal soaps and metal oxides. The composition of the present invention includes azodicarzenamide, inorganic salts such as zinc white and tribasic lead sulfate, metal soaps such as zinc stearate, lead stearate, and magnesium stearate, and one or two kinds of urea compounds. The above mixing is preferred. The amount of foaming aid added is 1:1 with the foaming agent.
It is used by blending in the range of ~1:0.1.

The resin powder composition of the present invention can be produced by simply tri-blending the polyethylene resin powder, organic peroxide, and blowing agent. There may be a drawback that the foam separates and there is a significant difference in its initial foamability. Therefore, in the present invention, these mixed compositions are preferably maintained at a temperature higher than the melting point of the polyethylene resin and higher than the decomposition temperature of the organic peroxide in an extruder so as not to cross-link and foam, and then melted and mixed to form granules. , and then ground in a known manner. A common method of pulverization is, for example, mechanically pulverizing with a pulverizer. The melting point of the polyethylene resin is the peak temperature when a melting curve is measured using a differential scanning calorimeter at a heating rate of 8° C./min. If necessary, other additives, such as coloring pigments, antioxidants, weathering agents, resin stabilizers, antistatic agents, lubricants, etc., may be appropriately blended into the resin powder composition of the present invention.

The particle size of the resin powder composition of the present invention should be 500 microns or less, preferably in the range of 70 to 250 microns, to obtain a good coating film. The particle size of the powder varies depending on the various coating methods; if the particle size is too large, uneven coating will occur, and a smooth coating will not be obtained, resulting in poor appearance. For example, electrostatic coating uses powder with a relatively fine particle size;
In particular, those of 150μ or less are preferably used. Powders as coarse as 350 microns may be used in the scattering method and the fluidized dip coating method, but powders in the range of 70 to 250 microns are preferably used.

Resin powder generally has a distribution in particle size, and the particle size in the present invention is expressed as a representative value of the particle size that occupies the largest proportion by weight in the whole. As a method for measuring the particle size, the sieving method using a standard sieve (defined in JIS Z8801) is used.

Metal objects to which the powder composition of the present invention is applied include:
These metals include iron, steel, zinc, nickel, aluminum, copper, and alloys of these metals, and mild steel wires and plates are widely used.

In the foam coating on metal in the present invention, a resin powder composition is applied to the metal surface, and the resin is heated above the decomposition temperature of the foaming agent to melt and crosslink and foam. As a specific method for coating the metal surface, a fluidized dip coating method, an electrostatic dipping method, an electrostatic spraying method, etc. are used.

(Example) The present invention will be explained in more detail with reference to Examples below.
The invention is not limited to this example.

For the foamed coating films obtained in each example, (1) film appearance, (2) foaming ratio, (3) cell structure and uniformity, and (4) sound insulation properties were determined by the following methods. .

(1) Appearance of the coating: If no trace of defoaming of air bubbles with a size of 50μ or more is observed on the coating surface by naked eye observation, it is considered good.
Those with large traces of defoaming were judged to be defective.

(2) Foaming ratio: The foaming ratio is B, and the density of the foamed wave membrane is ρ'
, when the resin density is ρ, it was determined as B=ρ/ρ'.

(3) Cell structure and uniformity: The cross section of the film was observed using a microscope to examine the size of the bubbles, the distribution and uniformity of the foam cells. A case where the bubble size was 500 μm or less and was uniformly distributed was considered good, and a case where there were many occurrences of coarse bubbles, particularly cavities or continuous bubbles, was judged as poor.

(4) Sound insulation: If a high-pitched metallic sound is generated when a steel wire with a diameter of 4 mm is nailed to the coating, the sound insulation is considered to be poor, and if the metallic sound disappears and becomes a low sound, the sound insulation is considered to be good. did.

Examples 1, 2, 3.4 Base resin polyethylene (A); MI = 25 f,...' 10 minutes,
LOB = 11/1030, number of terminal methyl groups 229
pieces/1030 [B); MI=50r710 minutes, LOB=14 pieces/1
0” O.

Number of terminal methyl groups = 30 pieces/10"0 [0); MI = 1ot/lo minute, LOB = 4.5 pieces 71
030° Number of terminal methyl groups = 22 pieces/10"0 (D); Mx = s', /10 minutes, LOB = 5.5 pieces/1
03C1 number of terminal methyl groups = 24/10''0 was used, and 1,1-bis(tert-butylnozo-oxyisopropyl)benzene (
Made by Kayaku Thule, 1 hour half-life Temperature = 141°C, trade name, Parkadotsu 14), 1% by weight and azodicarzenamide (made by Hydration Kasei, trade name, Vinyhole SW"?, common temperature) as a blowing agent. = 170℃, particle size = 15μ)
4% by weight, and 0.5% of carton black as a black pigment.
% by weight, premixed using a drum-type blender, melt-kneaded using a Tanabe Tekko type 40-hole φ extruder at a resin temperature of 130° C., and granulated into particles with a diameter of about 3 mm. Next, it is mechanically crushed using a Honkawa Micron Victory Mill crusher.
The resin powder composition for foam coating was classified using a 350μ sieve and had a particle size of 250μ distributed in the range of 74 to 350μ. This powder composition was fluidized in a fluidized bath, and a copper plate of thickness 1.6 mm and size 40 x 100 cm, which had been preheated at 300°C for 4 minutes, was immersed therein for 5 seconds, and then heated to 180°C.
Baked for 1 minute, then naturally cooled to a thickness of about 1.
A foam coating of the fifth throat was obtained.

This foamed coating was examined for its appearance, foaming ratio, cell structure and uniformity, and coating performance such as sound insulation, and the results are shown in Table 1. Further, when the degree of crosslinking of the foamed coating was measured as a decalinne soluble content, an insoluble content of 40 to 60% was obtained. As is clear from Table 1, in all cases, the appearance was good and the foaming ratio was sufficiently high.
In addition, a foamed coating film with uniform and fine bubble cells and high sound insulation properties has been obtained.

The following margin comparison examples 1, 2, 3.4 were used in Example 1. [In place of lyethylene (E);
MI=2 (1/10 min, LOB=3.5 pieces/103C
Number of 1-terminal methyl groups = 1 (is'/1030[F];
MI=79710 min, LCB=0.5 pieces/1θ30° number of terminal methyl groups=17 r/1030CG]; MI=
1.5f/10min, LOB = 5.3([11030
, number of terminal methyl groups = 23 t/1030 [H];
Foam coating was carried out in the same manner as in Example 1, except that Mx = 25F, /10 minutes, LOB = 0 pieces / 1030, number of terminal methyl groups = 12f / 1030 (Dow Chemical Group, trade name, Dowlex 2552) was used. A resin powder composition was prepared, and under the same conditions as in Example 1,
A foamed coating was obtained. The performance of this foam coating was tested and the results are shown in Table 2.

The following are the types of margin polyethylene: [E), CF), (Hl) When the degree of crosslinking of the foamed coating film was measured as the decalinne soluble content, it was found that there was almost no crosslinking with an insoluble content of 5% or less. On the other hand, the foamed coating film [G] had a decalinne solubility of 5.
At 0%, the crosslinkability was high, but the resin MI was low, foaming was incomplete, the coating film was poor in smoothness, and the coating film had a highly uneven surface.

The foamed coating films of (El, rF) and (H) have almost no crosslinking, so they have poor bubble retention stability during foaming, resulting in coarse cells, non-uniform foaming, and poor sound insulation with many open cells. It is a coating.

Examples 5, 6, 7.8 Polyethylene (Al used in Example 1) and ethylene-vinyl acetate copolymer (EVA; manufactured by Fukaisei Co., Ltd. EM-5822)
, Mt = 22), ethylene-ethyl acrylate copolymer (EEA; DPDJ 802 manufactured by Nippon Unicar)
6, Mt=17), ethylene-acrylic acid copolymer (BAA; Mitsubishi Yuka A-210M, MI=9)
, ethylene ionomer resin (manufactured by Mitsui Polychemicals)
A resin powder composition for foam coating was prepared in the same manner as in Example 1, except that 25% by weight of each of Surlyn 1652 (MI=5) was blended, and a foam coating was obtained under the same conditions as in Example 1.

The performance of this foam coating was tested and the results are shown in Table 3.

A good foamed 4IL film was obtained, and Example 5゜6
．． 7 has a soft coating surface, excellent cushioning properties, and high impact resistance. The foam coating of Example 7.8 had excellent adhesion to the copper plate.

Below is the blank space Example 9 Evaluation was carried out in the same manner as in Example 1 except that dicumyl peroxide (manufactured by NOF Corporation, ) ξ-cumyl D (decomposition temperature = 137°C) was used as the organic peroxide, and the results are shown in Table 4. are summarized in

Example 10 The blending amount of the organic peroxide in Example 9 was changed to %, and the blowing agent was changed to Vinyhole SE"30 (manufactured by Eiwa Kasei, azodicarzenamide type, particle size 15μ, decomposition temperature = 142°C). The evaluation was carried out in the same manner as in Example 9, except that
They are summarized in the table.

Example 11 The amount of organic peroxide compounded in Example 9 was doubled, and the type of blowing agent was 4,4'-oxybis-benzenesulfonylhydrazide (Eiwa Kasei, Neocelzen I" 1000. Particle size 25 μm). , decomposition temperature = 155°C) was evaluated in the same manner as in Example 9, and the results are summarized in Table 4.

Example 12.13 Among the composition contents of Example 1, zinc oxide was added as an auxiliary agent in place of the sample azodicarzenamide (particle size 10μ) as the foaming agent, and the decomposition temperature was adjusted to 160 ° C. The evaluation was carried out in the same manner as in Example 1 except that the amount of the agent was changed to 1% and 8%, and the results are summarized in Table 4 as Examples 12 and 13.

Example 14 Among the formulation contents of Example 1, the blowing agent was replaced with the reagent azodicarzenamide (particle size 35μ), zinc oxide was blended as an auxiliary agent, the decomposition temperature was adjusted to 160°C, and the blowing agent The evaluation was carried out in the same manner as in Example 1, except that the particle size was made coarser, and the results are summarized in Table 4.

Comparative Examples 5 and 6 The composition of Example 1 was used, but the amount of organic peroxide was 0.
．． Evaluated in the same manner as in the example except for 1% by weight and 5TL amount%,
The results are summarized in Table 4 as Comparative Example 5.6.

In Comparative Example 5, the lack of Kurihashi degree resulted in coarse cells, resulting in a foamed coating with a large number of defoamed surfaces, and in Comparative Example 6, due to excessive crosslinking, the resulting coating was incompletely foamed and had a low expansion ratio.

Comparative Example 7 Among the composition contents of Example 10, 2.0% of the organic peroxide was added.
5-dimethyl-2,5-di(tert-butylperoxy)hexine-3 (Nihon Yushi Co., Ltd., Verhexin 23B1
The evaluation was carried out in the same manner as in Example 10, except that 1% by weight was used instead of (decomposition temperature = 148°C), and the results are shown in Table 4. Regarding the relationship between the decomposition temperatures of the organic peroxide and the blowing agent, since the decomposition temperature of the blowing agent is low, the blowing agent decomposes before the organic peroxide decomposes, making it impossible to obtain a good foamed coating.

Comparative Examples 8 and 9 The composition of Example 1 was used, but the amount of blowing agent was 0.3% by weight,
The samples were bound at 15% by weight and evaluated in the same manner as in Example 1, and the results are summarized in Table 4 as Comparative Examples 8 and 9.

Comparative Example 10 The particles of the resin composition prepared in Example 1 were mechanically crushed and classified using an 840μ sieve to obtain a resin powder composition for foam coating with a particle size of 700μ distributed in the range of 500 to 840μ. It was adjusted and evaluated in the same manner as in Example 1. Although the foamed cells were uniform and fine and the film exhibited high sound insulation properties, the appearance of the film, especially the surface, was highly uneven due to the coarse powder particles, resulting in a foamed film with poor appearance.

Example 15 In place of the low density polyethylene used in Example 1, ethylene vinyl acetate copolymer (EVA; manufactured by Seikasei Co., Ltd., EM-58) was used.
22, MI=22, vinyl acetate concentration=8%) was evaluated in the same manner as in Example 1, and the results are summarized in Table 4. The obtained foam coating had excellent elasticity and high sound insulation properties.

Example 16 The resin powder composition for foam coating of Example 1 was added to 149
The powder was reclassified using a μ sieve to prepare a powder with a particle size of 149μ or less. This powder composition can be used to prepare polished steel plates with a thickness of 0.8 mm, zinc plates, aluminum plates, brass plates with a thickness of 0.3 mm.
It was applied to a stainless steel plate (SUS430) and a tin plate using an electrostatic coating method. For electrostatic painting, we used Sturge kit type electrostatic powder coating equipment made by Sames, and the voltage was 60KV.
, current 150 μA, spray gun primary pressure 0-5 K
The powder composition was applied under the conditions of l/ctrr', and then 2
Heated in an oven heated to 00°C for 5 minutes until the film thickness was 1.
A cross-linked foam coated plate with a good appearance was obtained.

Margin below

Claims (2)

[Claims] (1) Ethylene-vinyl acetate copolymer with a melt index in the range of 4 to 60, or a long chain branching degree of the polymer chain and a terminal methyl group of 3 or more and 18 or more per 10^3 carbon atoms, respectively. 100 parts by weight of polyethylene, 0.2 to 3.0 parts by weight of an organic peroxide whose half-life temperature for 1 hour is in the range of 105°C to 160°C, and a decomposition rate equal to or higher than that of the organic peroxide. 0.5 to 10 parts by weight of a blowing agent having a temperature, and a particle size of 50
Resin powder composition for foam coating on metal, characterized by having a particle size of 0 μ or less (2) An ethylene vinyl acetate copolymer with a melt index in the range of 4 to 60, or a long chain branching degree of the polymer chain and a terminal methyl group of 3 or more and 18 or more per 10^3 carbon atoms, respectively. 100 parts by weight of polyethylene, 0.2 to 3.0 parts by weight of an organic peroxide whose half-life temperature for 1 hour is in the range of 105°C to 160°C, and a decomposition rate equal to or higher than that of the organic peroxide. After mixing with 0.5 to 10 parts by weight of a blowing agent having a temperature and kneading while maintaining the temperature to be above the melting point of the ethylene vinyl acetate copolymer or polyethylene and below the decomposition temperature of the organic peroxide, A method for producing a resin powder composition for foam coating on metal, characterized by pulverizing it to a diameter of 500μ or less