JP5013529B2 - Slowly-flammable polyethylene resin particles, method for producing the same, polyethylene foam beads using the same, and resin molded products - Google Patents

Description

  The present invention relates to a slow-flammable foamable polyethylene resin particle, a production method thereof, a polyethylene-based foamed bead obtained by foaming the slow-flammable foamable polyethylene-based resin particle, the slow-flammable foamable polyethylene-based resin particle or The present invention relates to a slow-flammable foamed polyethylene resin molded product obtained by foam molding of the polyethylene foam beads.

  Compared with expanded polystyrene resin molded products, expanded polyethylene resin molded products make use of the characteristics of excellent resilience of impact resistance, bending deflection, and repeated stress strain, and as packaging materials for precision parts and heavy products, Taking advantage of its excellent heat resistance and oil resistance, it is widely used as automotive parts such as shock absorbers, bumpers and floor spacers.

Expandable polyethylene resin particles obtained by impregnating a polyethylene resin with a foaming agent are known. However, polyethylene has a property of being easily burned, and in particular, it is difficult to meet the flammability standards of automobile parts.
When the brominated flame retardant used in the conventional polystyrene system is used for the polyethylene resin, there is a problem in that the polyethylene is deteriorated during extrusion and the strength and foamability are impaired.

  In addition, the expanded polyethylene resin particles have the property of being easily permeable to the foaming agent. Therefore, the foaming agent dissipates within a few hours after production and the foamability is significantly reduced. It is necessary to use expanded particles. For this reason, it is necessary to install a pre-foaming machine and a molding machine near the foaming agent impregnation equipment, and the production base is limited. Therefore, the transportation cost of foamed particles and molded products is high, which is economically disadvantageous.

  In addition, since the foamed polyethylene-based resin molded product has inferior compressive strength compared to the foamed styrene-based resin molded product, it is necessary to lower the expansion ratio compared to the foamed styrene-based resin molded product. It was disadvantageous in cost compared with the foamed styrene resin molded product.

  As a method for solving these problems, a crosslinking agent is added to the polyethylene resin particles, and in the dispersion medium composed of water, low-boiling alcohols and ketones, the crosslinking treatment is performed by heating, and the dispersion medium is expanded. A method of impregnating the crosslinked resin particles as an agent has been proposed (Patent Document 1).

  In addition, many methods have been proposed for obtaining modified polyethylene resin particles by impregnating polyethylene resin particles with a vinyl aromatic monomer in which a polymerization initiator and a crosslinking agent are dispersed to carry out polymerization and crosslinking. (Patent Documents 2 to 7).

Japanese Patent Publication No.53-25857 Japanese Patent Publication No.58-053003 Japanese Examined Patent Publication No. 45-032623 Japanese Patent Laid-Open No. 01-284536 JP-A-48-101457 JP-A-49-05473 JP 49-097884 A

  However, a crosslinking agent is added to the above-described polyethylene resin particles, and the crosslinking treatment is performed by heating in a dispersion medium composed of water, low-boiling alcohols and ketones, and the dispersion medium is used as a foaming agent. With respect to the method of impregnating the resin particles, the foaming agent is excellent, but the foaming property is extremely low. That is, low-boiling alcohols and ketones do not perform a sufficient function as a foaming agent for polyethylene resin particles.

  On the other hand, a method for obtaining a modified polyethylene resin particle by impregnating a polyethylene-based resin particle with a vinyl aromatic monomer in which a polymerization initiator and a crosslinking agent are dispersed to carry out polymerization and crosslinking is as follows. Although the retention of foaming agent and the strength of foamed molded products are improved by increasing the ratio of vinyl aromatic monomers, it is necessary to considerably increase the ratio of vinyl aromatic monomers in order to obtain sufficient foaming agent retention. In this case, the impact resistance, the bending deflection, and the resilience of repeated stress strain, which are the characteristics of polyethylene, cannot be obtained.

  The present invention has been made in view of the above, and suppresses the dissipation of the foaming agent, which has been a problem with conventional expandable polyethylene resin particles, and has excellent long-term foam moldability. Expandable polyethylene resin particles having excellent strength while maintaining the resilience of impact resistance, bending deflection, and repeated stress strain, which are the characteristics of resin molded products, a method for producing the same, and polyethylene foam beads and foamed polyethylene using them -Based resin molded products are provided.

  The inventors of the present invention have made extensive studies on the slow-flammable foamable polyethylene resin particles that solve the above-mentioned problems. The existence of polyethylene core particles containing a specific amount of magnesium hydroxide having excellent flame retardancy in an extruder. Below, the slow-flammable foamable polyethylene resin particles obtained by polymerizing monomers such as styrene and butyl acrylate and impregnating the foaming agent can improve the retention of the foaming agent. It has been found that a foamed molded product having high strength can be obtained while maintaining high foamability even when dispersed, and the present invention has been completed.

That is, the present invention is as follows.
The present invention includes [1] ethylene-vinyl acetate copolymer, linear low-density polyethylene and acrylonitrile-styrene copolymer as resin components, and 15 to 30 magnesium hydroxide per 100 parts by weight of the resin component. The present invention relates to slow-flammable foamable polyethylene resin particles obtained by polymerizing a monomer in the presence of core parts containing parts by weight and impregnating a foaming agent.

  The present invention also relates to [2] slow-flammable foamable polyethylene resin particles according to the above [1], wherein the blending weight ratio between the core particles and the monomer is 10/90 to 60/40.

  In the present invention, the resin component of [3] core particles is 10 to 80 parts by weight of ethylene-vinyl acetate copolymer, 10 to 80 parts by weight of linear low density polyethylene, and 1 to 50 of acrylonitrile-styrene copolymer. The present invention relates to the slow-flammable foamable polyethylene resin particles according to the above [1] or [2], which comprises 100 parts by weight in total.

  The present invention also relates to the slow-flammable foamable polyethylene resin particles according to the above [1], [2] or [3], wherein the [4] monomer is a mixture of styrene and butyl acrylate.

  The present invention also relates to the slow-flammable foamable polyethylene resin particles according to the above [4], wherein the [5] butyl acrylate blending ratio is 0.5 to 10% by weight based on the total amount of monomers.

  The present invention also relates to the slow-flammable foamable polyethylene resin particles according to any one of the above [1] to [5], wherein [6] the particle diameter of the core particles is 0.1 to 3.0 mm.

  In addition, the present invention provides [7] a resin component containing an ethylene-vinyl acetate copolymer, a linear low density polyethylene and an acrylonitrile-styrene copolymer, and magnesium hydroxide 15-30 with respect to 100 parts by weight of the resin component. It is characterized by blending parts by weight, melt-kneading and then finely granulating into core particles, suspending in an aqueous medium, adding a monomer to this suspension, and performing polymerization and impregnation with a blowing agent. The present invention relates to a method for producing slow-flammable polyethylene resin particles.

  In addition, the present invention provides the retardation described in [7] above, in which a polymerization initiator and a crosslinking agent are dispersed in advance in the monomer [8] and added to perform polymerization, crosslinking, and impregnation with a foaming agent. The present invention relates to a method for producing flammable foamable polyethylene resin particles.

  In the present invention, [9] the resin component for core particles is composed of 10 to 80 parts by weight of ethylene-vinyl acetate copolymer, 10 to 80 parts by weight of linear low density polyethylene, and 1 to 50 of acrylonitrile-styrene copolymer. The present invention relates to the method for producing slow-flammable foamable polyethylene resin particles according to the above [7] or [8], wherein the weight parts are blended so that the total amount becomes 100 parts by weight.

  The present invention also provides [10] the slow-flammable polyethylene resin particles according to any one of [1] to [6] or the production method according to any one of [7] to [9]. The present invention relates to a polyethylene foam bead obtained by foaming the slow-flammable foamable polyethylene resin particles obtained by the above.

  The present invention also relates to [11] a slow-flammable foamed polyethylene resin molded product obtained by foaming the polyethylene foamed beads described in [10].

  According to the present invention, the foaming polyethylene system which suppresses the dissipation of the foaming agent, is excellent in long-term foam moldability, and is excellent in strength while maintaining the resilience of impact resistance, bending deflection, and repeated stress strain. Resin particles, a production method thereof, polyethylene foam beads using them, and foamed polyethylene resin molded products can be provided.

Hereinafter, embodiments of the present invention will be described.
The present invention comprises an ethylene-vinyl acetate copolymer, a linear low density polyethylene and an acrylonitrile-styrene copolymer as resin components, and 15-30 parts by weight of magnesium hydroxide with respect to 100 parts by weight of the resin component. This is a slow-flammable foamable polyethylene resin particle obtained by polymerizing a monomer in the presence of the core particle and impregnating with a foaming agent. When the amount of magnesium hydroxide is less than 15 parts by weight, the effect of slow flame retardancy is inferior. On the other hand, when it exceeds 30 parts by weight, the foamability and the strength of the molded product are inferior.

The core particles used in the present invention are prepared by melting a resin component containing ethylene-vinyl acetate copolymer, linear low density polyethylene and acrylonitrile-styrene copolymer as essential components, and a resin for core particles containing magnesium hydroxide. It is obtained by kneading and then making fine particles. The fine granulation can be performed by, for example, melting and kneading and extruding with an extruder and then cooling and solidifying and then cutting with a cutter such as a pelletizer.
The mixing ratio of magnesium hydroxide is 15 to 30 parts by weight with respect to 100 parts by weight of the resin component, and the resin component is 10 to 80 parts by weight of ethylene-vinyl acetate copolymer in a total of 100 parts by weight, linear. A low density polyethylene of 10 to 80 parts by weight and an acrylonitrile-styrene copolymer of 1 to 50 parts by weight are preferred from the viewpoint of foamability and the strength of the molded product obtained, and the amount of acrylonitrile-styrene copolymer is 2 to 20 More preferred are parts by weight.
Magnesium hydroxide used for the core particles preferably has an average particle diameter of 1.2 to 7.0 μm, and the amount of magnesium oxide remaining by ignition is 60 to 70% by weight of magnesium hydroxide.
The ethylene-vinyl acetate copolymer used for the core particles has a vinyl acetate content of 3 to 20% by weight and a density of 0.95 (g / cm ³ ) or less, and a melt mass flow rate. Is 1.5 to 4.0 (g / 10 min), and the Picat temperature (Bigat softening point, JISK7206) is preferably 60 to 110 ° C.
The linear low-density polyethylene resin used for the core particles has a density of 0.94 (g / cm ³ ) or less, a melt mass flow rate of 1.5 to 4.0 (g / 10 min), and a Picut temperature ( The bigat softening point is preferably 80 to 120 ° C.
The acrylonitrile-styrene copolymer used for the core particles preferably has a weight average molecular weight of 70,000 to 400,000.
Furthermore, it is preferable that the particle diameter of the core particle is 0.1 to 3.0 mm.

(1) Polymerization and Crosslinking The polyethylene resin core particles containing magnesium hydroxide obtained above are suspended in an aqueous medium to form a suspension. Dispersion in an aqueous medium is usually performed using an apparatus equipped with a stirring blade, and there are no restrictions on the conditions. Examples of the aqueous medium used in the present invention include ion exchange water.

  The core particles are preferably dispersed in an aqueous medium together with a dispersant. Examples of the dispersant used in the present invention include organic dispersants such as polyvinyl alcohol, polyvinyl pyrrolidone, and methyl cellulose, and poorly soluble inorganic salts such as magnesium phosphate and tricalcium phosphate.

  Furthermore, a surfactant can also be used. Examples of the surfactant include sodium oleate, sodium dodecylbenzenesulfonate, and other anionic surfactants and nonionic surfactants commonly used in suspension polymerization.

Next, a monomer is added to the suspension, and the resin particles can be impregnated and polymerized. As the monomer, it is preferable to use styrene and butyl acrylate in terms of foamability, molded product strength, and the like. It is preferable to previously dissolve the polymerization initiator and the crosslinking agent in the monomer. The butyl acrylate used as the monomer is preferably 0.5 to 10% by weight with respect to the total monomer, and the remainder is preferably styrene. If it is less than 0.5% by weight, high foamability cannot be obtained, and if it exceeds 10% by weight, shrinkage of the foamed particles becomes large, and conversely, it becomes difficult to obtain high foamability.
Preferably, it is 2 to 5% by weight, and more preferably 3 to 4% by weight can have good foamability.
In the present invention, monomers other than styrene and butyl acrylate can be added within a range that does not greatly impair the characteristics, and alkyl (meth) such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, and propyl methacrylate. Acrylate or the like can be used.

  The blending weight ratio between the core particles and the monomers such as styrene and butyl acrylate is preferably 10/90 to 60/40, and more preferably 20/80 to 50/50 in the former / latter weight ratio. More preferred. If it exceeds 60/40, the particles tend to be difficult to spheroidize. On the other hand, if it is less than 10/90, the impact resistance, heat resistance, and chemical resistance, which are the characteristics of the polyethylene resin, tend to decrease.

  The polymerization initiator used in the present invention is not particularly limited as long as it can be used in the suspension polymerization method of monomers such as styrene and butyl acrylate. For example, t-butyl peroxide, benzoyl peroxide, t- One or more organic peroxides such as butyl peroxy-2-ethylhexyl carbonate and t-butyl perbenzoate, and azo compounds such as azobisisobutylnitrile can be used.

The polymerization initiator may be added after being dissolved in a solvent and impregnated with polyethylene resin core particles. In this case, as a solvent for dissolving the polymerization initiator, aromatic hydrocarbons such as ethylbenzene and toluene, aliphatic hydrocarbons such as heptane and octane, and the like are used. When these are used, they are usually used at 3% by weight or less based on the styrene monomer.
Although the usage-amount of a polymerization initiator changes with kinds of polymerization initiator, generally the range of 0.1-1.0 weight% is preferable with respect to the monomer total amount.

  In the present invention, fatty acid monoamides such as oleic acid amide and stearic acid amide, fatty acid bisamides such as methylene bis stearic acid amide and ethylene bis stearic acid amide, etc. are dissolved in styrene, butyl acrylate or the above solvent as a bubble regulator. May be used. In this case, it is preferable to use 0.01 to 2 parts by weight with respect to 100 parts by weight of the total amount of monomers.

  The cross-linking agent used in the present invention mainly has a function of cross-linking polyethylene resin particles, and preferably does not decompose at the polymerization temperature of monomers such as styrene and butyl acrylate, but decomposes at the cross-linking temperature. And peroxides such as dicumyl peroxide, 2,5-t-butyl perbenzoate, and 1,1-bister sharub tipperoxycyclohexane. These may be used alone or in combination of two or more thereof. The amount is preferably 0.1 to 5% by weight based on the monomer.

In the present invention, the polymerization initiator and the crosslinking agent may be the same compound.
The addition of a monomer such as styrene or butyl acrylate containing a polymerization initiator and a crosslinking agent may be performed all at once or in portions.

  In the present invention, the polymerization temperature varies depending on the type of polymerization initiator used, but is preferably in the range of 60 to 105 ° C. Moreover, although a crosslinking temperature changes with kinds of crosslinking agent to be used, the range of 100-150 degreeC is preferable.

(2) Foaming agent impregnation step Subsequently, the foaming agent is impregnated into the resin particles during or after polymerization. In the impregnation with the foaming agent, the foaming agent is press-fitted into the container, and the temperature is usually raised to a temperature equal to or higher than the softening point of the resin particles, and the resin particles are impregnated.

As the foaming agent, a foaming agent that does not dissolve the resin particles, or those that slightly swell are preferable, specifically, aliphatic hydrocarbons such as propane, normal butane, isobutane, normal pentane, isopentane, normal hexane, cyclohexane, An alicyclic hydrocarbon such as cyclopentane is used. These may be used alone or in combination of two or more.
These foaming agents are usually used in an amount of 5 to 30% by weight based on the resin particles before impregnation with the foaming agent.

  The impregnation temperature of the foaming agent is preferably 80 ° C to 140 ° C, more preferably 90 ° C to 120 ° C. If the impregnation temperature of the foaming agent is less than 80 ° C., the impregnation of the foaming agent tends to be insufficient. On the other hand, when it exceeds 140 ° C., the resin particles tend to be flat. After the impregnation of the foaming agent is completed, the slow-flammable polyethylene resin particles can be obtained by discharging from the polymerization system.

  After dehydrating and drying the slow-flammable foamable polyethylene resin particles, a surface coating agent can be coated as necessary. Examples of the surface coating agent include zinc stearate, stearic acid triglyceride, stearic acid monoglyceride, castor oil, and antistatic agent.

  The slow-flammable foamable polyethylene resin particles of the present invention have a slow burning rate when formed into a molded product, can meet automobile member combustion standards, can improve foaming agent retention, and foaming agents. High foamability is maintained while maintaining high foamability even if the spills, and maintaining the resilience of impact resistance, bending deflection, and repeated stress strain, which are the characteristics of foamed olefin resin molded products. A flexible polyethylene resin molded product is obtained.

  Hereinafter, the present invention will be described in more detail based on examples. In addition, this invention is not restrict | limited to the following Example.

[Example 1]
[Production of polyethylene resin core particles in which magnesium hydroxide is blended with ethylene-vinyl acetate copolymer, linear low-density polyethylene, and acrylonitrile-styrene copolymer]
Magnesium hydroxide (manufactured by Kamishima Chemical Industry Co., Ltd., average particle size 3.5 μm, amount of magnesium oxide remaining due to high heat 65.8% by weight, trade name 10A) 600 g (20 parts by weight), vinyl acetate 15% by weight Contained ethylene-vinyl acetate copolymer (manufactured by Tosoh Corporation, Ultrasen 626, density 0.925 (g / cm ³ ), melt mass flow rate (MFR) 2.5 (g / 10 min), piccat temperature 65 ° C.) 780 g (26 parts by weight), linear low density polyethylene resin particles (manufactured by Tosoh Corporation, Nipolon 9P51A, density 0.91 (g / cm ³ ), melt mass flow rate 2.0 (g / 10 min), piccat temperature 96 ° C) 2100 g (70 parts by weight) and acrylonitrile-styrene copolymer particles (manufactured by Denki Kagaku Kogyo Co., Ltd., AS-XGS, Weight average molecular weight 127,000) 120 g (4 parts by weight) a Henschel mixer (Mitsui Miike Engineering Co., Ltd., was charged into FM10B), were mixed for 1 minute at 2000 rpm.
Next, this resin particle mixture was melt-extruded by an extruder (manufactured by Ikegai Co., Ltd., PCM-30 biaxial type, die diameter 3 mm, cylinder temperature 230 ° C., head temperature 230 ° C.), cooled and solidified, and then pelletized by Nakatani Machinery Co., Ltd. Manufactured, cutter speed scale 0.5, roll speed scale 0.5) to 0.7 to 1.1 cm to obtain polyethylene-based resin core particles.

[Impregnation / polymerization / crosslinking process]
In a 5 L pressure-resistant stirring vessel, 385 g of the above polyethylene resin core particles, 2100 g of deionized water, 11 g of tricalcium phosphate, and 0.025 g of sodium dodecylbenzenesulfonate were charged and stirred.
Next, 682 g of styrene monomer and 33 g of butyl acrylate were dissolved with 0.55 g of t-butyl peroxide, 3.4 g of benzoyl peroxide and 11.8 g of 1,1-bisbutylbutyl peroxycyclohexane. The polymer was added to the container and kept at 20 ° C. for 0.5 hour.
Thereafter, the temperature was raised to 88 ° C., and the temperature was maintained for 6 hours to polymerize the monomer. Next, after adding 1.1 g of tricalcium phosphate, 0.03 g of sodium dodecylbenzenesulfonate, and 4.4 g of calcium carbonate, the temperature was raised to 130 ° C. and kept for 5 hours for crosslinking.

Then, it cooled to 105 degreeC, cyclohexane 55g and butane (weight ratio of isobutane / n-butane = 4/6) 132g were inject | poured, and were hold | maintained for 6 hours.
After cooling to room temperature (25 ° C.), the polyethylene resin particles impregnated with the blowing agent were taken out and dehydrated and dried. Subsequently, the polymer particles were classified with a sieve having an opening of 3.35 mm and 1.7 mm to obtain 1100 g of resin particles. To the obtained resin particles, 2.9 g of fatty acid monoglyceride was added and mixed to obtain slow-flammable foamable polyethylene resin particles.
The obtained slow-flammable polyethylene-based resin particles are heated with steam using a foaming machine for foamed styrene-based resin (HBP-500LW manufactured by Hitachi Chemical Technoplant Co., Ltd.). Pre-foamed. Then, after aging for about 12 hours, using a foamed styrene resin molding machine (VS-300, manufactured by Daisen Industry Co., Ltd.), molding was performed at a molding pressure of 0.13 MPa, and a foamed polyethylene resin molded product (hereinafter referred to as “foam molding”). Product)).

The characteristic evaluation was performed by the following method and is shown in Table 1.
-Foaming agent content The resin particle is heated at 200 degreeC for 10 minute (s), and it calculates with the following formula | equation.
Amount of foaming agent (% by weight) = [(weight before heating−weight after heating) / weight before heating] × 100
-Foaming degree in boiling water at 100 ° C for 3 minutes Bulk magnification when foaming in boiling water at 100 ° C for 3 minutes.
-Flammability test The test was carried out at a molded product multiple of 30 ml / g. Molded product dimensions 100 x 350 x 12 (mm),
Combustion standard value 80 mm / min or less / 25% compressive strength Conforms to JIS K7220.
-Bending fracture distance Conforms to JIS A9511.
The amount of foaming agent after leaving the obtained slow-flammable foamable polyethylene resin particles in an open state at 20 ° C. for 48 hours was 6.5%, and the degree of foaming in 100 ° C. boiling water for 3 minutes was 30 ml / g. It was.

[Comparative Example 1]
In [Production of polyethylene-based resin core particles in which magnesium hydroxide is blended with ethylene-vinyl acetate copolymer, linear low-density polyethylene and acrylonitrile-styrene copolymer] described in Example 1, 300 g of magnesium hydroxide ( Except that the amount was 10 parts by weight), the same operation as in Example 1 was performed to obtain expandable polyethylene resin particles.
The resulting slow-flammable polyethylene resin particles were left open at 20 ° C. for 48 hours, the amount of foaming agent was 6.5%, and the degree of foaming in 100 ° C. boiling water for 3 minutes was 35 ml / g. It was.

[Comparative Example 2]
In [Production of polyethylene-based resin core particles in which magnesium hydroxide is blended with ethylene-vinyl acetate copolymer, linear low-density polyethylene and acrylonitrile-styrene copolymer] in Example 1, 1050 g of magnesium hydroxide (35 Except for the weight part), the same operation as in Example 1 was performed to obtain slow-flammable foaming polyethylene resin particles.
The resulting slow-flammable polyethylene resin particles were left open at 20 ° C. for 48 hours, the amount of foaming agent was 6.5%, and the degree of foaming in boiling water at 100 ° C. for 3 minutes was 20 ml / g. It was.

The slow-flammable foamable polyethylene resin particles of Example 1 of the present invention have a foaming agent amount of 6.5% even after leaving them at 20 ° C. for 48 hours, and suppress the dissipation of the foaming agent. Excellent long-term foam moldability. The foaming degree was 30 ml / g, and a foamed molded product having a density of 0.033 g / cm ³ could be obtained. In addition, the flammability is incombustible at 70 mm / min with respect to the standard 80 mm / min, and is excellent in bending deflection and stress strain recovery. On the other hand, the comparative example 1 with a reduced amount of magnesium hydroxide is inferior in combustibility, and the comparative example 2 in which the amount of magnesium hydroxide is increased is superior in combustibility, but the molded article magnification (foaming ratio) is small and the density is high. It was not possible to obtain a molded product having a low thickness.

  The slow-flammable foamable polyethylene resin particles of the present invention and the foam-molded product obtained therefrom can be used for various applications such as automobile members, packaging materials, and heat insulating materials.

Claims (11)

A core particle comprising ethylene-vinyl acetate copolymer, linear low-density polyethylene and acrylonitrile-styrene copolymer as a resin component, and 15-30 parts by weight of magnesium hydroxide with respect to 100 parts by weight of the resin component Late-flammable foamable polyethylene resin particles obtained by polymerizing monomers in the presence and impregnating a foaming agent. The flame retardant foamable polyethylene resin particles according to claim 1, wherein the blending weight ratio of the core particles and the monomer is 10/90 to 60/40. The resin component of the core particles is 10 to 80 parts by weight of ethylene-vinyl acetate copolymer, 10 to 80 parts by weight of linear low density polyethylene, and 1 to 50 parts by weight of acrylonitrile-styrene copolymer. The slow-flammable foamable polyethylene resin particles according to claim 1 or 2, which are contained as described above. The slow-flammable foamable polyethylene resin particles according to claim 1, 2 or 3, wherein the monomer is a mixture of styrene and butyl acrylate. 5. The slow-flammable foamable polyethylene resin particles according to claim 4, wherein the blending ratio of butyl acrylate is 0.5 to 10% by weight based on the total amount of monomers. The particle diameter of a core particle is 0.1-3.0 mm, The flame-retardant foaming polyethylene-type resin particle in any one of Claims 1-5. A resin component containing an ethylene-vinyl acetate copolymer, a linear low-density polyethylene and an acrylonitrile-styrene copolymer, and 15-30 parts by weight of magnesium hydroxide are blended with 100 parts by weight of the resin component, and melt-kneaded. Then, the particles are finely divided into core particles, suspended in an aqueous medium, a monomer is added to the suspension, and polymerization and foaming agent impregnation are performed. Manufacturing method. The production of the slow-flammable foamable polyethylene resin particles according to claim 7, wherein a polymerization initiator and a crosslinking agent are dispersed in advance in the monomer and added to perform polymerization, crosslinking and impregnation with a foaming agent. Method. The resin component for the core particles is composed of 10 to 80 parts by weight of an ethylene-vinyl acetate copolymer, 10 to 80 parts by weight of a linear low density polyethylene and 1 to 50 parts by weight of an acrylonitrile-styrene copolymer. The method for producing slow-flammable foamable polyethylene resin particles according to claim 7 or 8, wherein the composition is blended as described above. The slow-flammable foamable polyethylene resin particles according to any one of claims 1 to 6 or the slow-flammable foamable polyethylene resin particles obtained by the production method according to any of claims 7 to 9 is foamed. Polyethylene foam beads obtained. A slow-flammable foamed polyethylene resin molded product obtained by foaming the polyethylene foam beads according to claim 10.