JP5378638B2 - Foamable resin composition and foamed sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an expandable resin composition and an expanded sheet, suitable for, e.g. wallpaper, leather and a flooring material having excellent expandability without causing discoloration after expansion. <P>SOLUTION: The expandable resin composition comprises 100 pts.wt. of an ethylenic copolymer resin, 2-10 pts.wt. of a foaming agent and 2-50 pts.wt. of magnesium hydroxide surface treated with a phosphoric ester. The expanded sheet is obtained by molding the expandable resin composition. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a foamable resin composition and a foamed sheet, and more specifically, wallpaper, leather, flooring, etc. that have good foamability, do not generate gas that pollutes the environment during combustion, and have excellent flame retardancy. And a foam sheet using the composition.

  Conventionally, from the viewpoint of environment and safety, wallpaper using an olefin resin, for example, Patent Documents 1 and 2 has been proposed as an alternative to vinyl chloride resin. Further, foamed sheets having good foaming properties, for example, Patent Documents 3 and 4 have been proposed even when an olefin-based resin is highly filled with an inorganic filler or flame retardant.

  However, these methods have a problem of coloring that is considered to be caused by the action of the foaming agent residue and the inorganic filler during foaming.

Japanese Patent Laid-Open No. 5-200948 Japanese Patent Laid-Open No. 10-17724 JP 2000-26639 A Japanese Patent Laid-Open No. 2000-230068

  The present invention solves the above-mentioned problems, and is particularly suitable for olefinic foamable resin compositions and foamed sheets, such as wallpaper, leather, flooring, etc., which are not colored after foaming and have excellent foamability. The purpose is to provide.

The means taken by the present invention to achieve the above object is to use magnesium hydroxide whose surface is treated with phosphate ester, 2 to 10 parts by weight of an azo chemical foaming agent, based on 100 parts by weight of ethylene-vinyl acetate copolymer resin. Ru der that the picture, characterized in that by molding the 2-50 parts comprising foamable resin composition (claim 1).

  ADVANTAGE OF THE INVENTION According to this invention, the olefin type foamable resin composition and foam sheet which were excellent in foamability by suppressing the coloring after foaming can be provided.

  The foamable resin composition and foamed sheet of the present invention contain 2 to 10 parts by weight of a foaming agent and 2 to 50 parts by weight of magnesium hydroxide whose surface is treated with a phosphoric acid ester with respect to 100 parts by weight of an ethylene copolymer resin. A foamable resin composition, and a foamed sheet for molding the foamable resin composition. Details will be described below.

  Examples of the ethylene copolymer resin used in the present invention include ethylene-vinyl acetate copolymer resin (hereinafter abbreviated as EVA), ethylene-methyl acrylate copolymer resin (hereinafter abbreviated as EMA), and ethylene-ethyl acrylate copolymer resin. (Hereinafter abbreviated as EEA), ethylene-methyl methacrylate copolymer resin (hereinafter abbreviated as EMMA), and the like. These may be used alone or in combination of two or more.

  When magnesium hydroxide is added to the ethylene copolymer resin, foamability and flame retardancy are improved. The magnesium hydroxide used in the present invention needs to be surface-treated with a phosphate ester. Moreover, as a particle size of magnesium hydroxide, the average particle size is preferably 0.5 to 10 μm, more preferably 1 to 2 μm. The amount of magnesium hydroxide added is 2 to 50 parts by weight, preferably 5 to 20 parts by weight, based on 100 parts by weight of the ethylene copolymer resin. When the addition amount is less than 2 parts by weight, the foamability is lowered, and when it exceeds 20 parts by weight, the workability and foamability are lowered.

  Coloring after foaming is considered to be particularly affected by metal hydroxides among inorganic fillers. Therefore, it is considered that coloring can be suppressed by using surface-treated magnesium hydroxide and preventing the action with the foaming agent residue. As the surface treatment agent for magnesium hydroxide, phosphate ester treatment, fatty acid treatment, silane coupling treatment, and the like can be considered. However, the fatty acid treatment has a relatively weak bond with magnesium hydroxide, so it is easily removed by heat processing, and the effect cannot be obtained. Although the silane coupling treatment is difficult to come off, the foamed sheet to which the magnesium hydroxide is added has poor foamability. In the phosphoric acid ester treatment, the treatment is difficult to come off, and the foamability of the foamed sheet is good. Therefore, the surface treatment agent is limited to the phosphoric acid ester treatment.

〔リン酸モノエステル、ジエステルの場合、式中、Ｒ_１はＨを表し、Ｒ_２はＨ、Ｃ_８−Ｃ_３０のアルキル基、Ｃ_６−Ｃ_３０のアリール基を表し、Ｒ_３はＣ_８−Ｃ_３０のアルキル基、Ｃ_６−Ｃ_３０のアリール基を表す。また、リン酸トリエステルの場合、式中Ｒ_１、Ｒ_２、Ｒ_３はＣ_１−Ｃ_８のアルキル基、Ｃ_６−Ｃ_１０のアリール基を表す。〕 Examples of the phosphoric acid ester used for the surface treatment of magnesium hydroxide include phosphoric acid monoesters, diesters, triesters, or composites thereof, which are represented by the general formula (1).
(1)

[In the case of phosphoric acid monoester and diester, R ₁ represents H, R ₂ represents H, a C ₈ -C ₃₀ alkyl group, a C ₆ -C ₃₀ aryl group, and R ₃ represents C ₈ alkyl -C _30, an aryl group of C 6 _{-C 30.} In the case of a phosphoric acid triester, R ₁ , R ₂ , and R ₃ represent a C ₁ -C ₈ alkyl group and a C ₆ -C ₁₀ aryl group. ]

  Magnesium hydroxide can also be used in combination with other inorganic fillers (hereinafter, inorganic fillers are other than magnesium hydroxide). Examples of inorganic fillers include hydrated metal compounds such as aluminum hydroxide, calcium hydroxide, hydrotalcite, calcium carbonate, talc, mica, clay, barium sulfate, and the like. You may use together with magnesium oxide. The particle size of the inorganic filler is preferably an average particle size of 0.1 to 20 μm, more preferably 0.5 to 10 μm. The total amount of magnesium hydroxide and inorganic filler added is generally 30 to 100 parts by weight with respect to 100 parts by weight of the ethylene copolymer resin.

  As the foaming agent used in the present invention, a thermal decomposition type foaming agent known in this technical field can be used. For example, azo compounds such as azodicarboxylic acid amide (ADCA) and azobisisobutyronitrile (AIBN). And chemical blowing agents such as sulfonyl hydrazide compounds such as P, P′-oxybisbenzenesulfonyl hydrazide (OBSH) and nitroso compounds such as dinitrosopentamethylenetetramine (DPT). These may be used alone or in combination of two or more. Among these, azodicarboxylic acid amide is preferable from the viewpoint of processability and stability. The addition amount of the foaming agent is 2 to 10 parts by weight with respect to 100 parts by weight of the ethylene-based copolymer resin. When the amount is less than 2 parts by weight, the foaming ratio is not sufficiently obtained. The effect is saturated. Foam regulators are used to adjust the decomposition temperature of the foaming agent. For example, additives such as metal soaps, metal oxides, urea compounds, acid anhydrides, and organic acids can be used alone or in combination. . The amount added is about 0.1 to 5 parts by weight.

  Other additives include plasticizers, stabilizers, light stabilizers, ultraviolet absorbers, antioxidants, lubricants, fillers, flame retardants, antibacterial agents, colorants, deodorants, etc. It can be suitably added to the ethylene copolymer resin as long as the purpose is not impaired.

  The foamable resin composition of the present invention can be mixed using a known mixing apparatus, and examples of the mixing apparatus include a Banbury mixer, a kneader, and an extruder. Moreover, it can be formed into a sheet using a known apparatus, for example, a roll processing apparatus such as a calendar apparatus, an extruder, an inflation apparatus, or the like.

  Furthermore, in order to improve the designability, printing may be performed by various methods or embossing may be performed.

  The present invention will be described in more detail with reference to examples. In addition, all the compounding parts of an Example and a comparative example are a weight part.

<Examples 1-2>
After mixing the formulations shown in Table 1 with a Henschel mixer, using an inverted L-type calendar molding machine having a temperature of 140 ° C., sheeting was performed to a sheet thickness of 0.1 mm to obtain an unfoamed sheet. This unfoamed sheet was laminated with a 0.11 mm backing paper and then heated in an oven at 220 ° C. for 70 seconds to cause foaming. The colorability and foaming ratio after foaming of this wallpaper were measured. The results are shown in Table 1.

<Comparative Examples 1-5>
After mixing the formulations shown in Table 1, wallpaper was prepared in the same manner as in Examples 1 and 2, the same measurement was performed, and the results are shown in Table 1.

The evaluation items, evaluation methods, and evaluation criteria of Examples and Comparative Examples are shown below.
<Colorability>
Measurement was not performed according to JIS Z8722 4 (spectroscopic measurement method), and a value a * indicating redness was calculated according to JIS Z8730 6.1, and the colorability was evaluated.
If a * is less than −0.5, redness is hardly recognized visually, but if it is −0.5 or more, redness is visually recognized.
○: Less than a * −0.5 ×: a * −0.5 or more <Foaming ratio>
The thickness of the sheet before foaming and the thickness of the sheet after foaming were measured, and the foaming ratio was calculated by the following formula.
When the expansion ratio is 5 times or more, a concavo-convex pattern is easily formed by embossing performed after foaming, and the design and texture are improved. If the expansion ratio is 3 times or more and less than 5 times, the uneven pattern tends to be difficult to enter, but it is at a level that can be used for both design and texture. When the expansion ratio is less than 3 times, the design and texture are both inferior and cannot be used.
○: Foaming ratio is 5 times or more.
Δ: Foaming ratio of 3 times or more and less than 5 times.
X: Foaming ratio is less than 3 times.

ＥＶＡ ：エチレン酢酸ビニル共重合樹脂
（東ソー製 ＭＦＲ＝１．５、酢酸ビニル含有２０％）
水酸化マグネシウム（１）： リン酸エステル処理（協和化学製 キスマ５Ｊ）
水酸化マグネシウム（２）： 無処理（ＴＭＧ製 ファインマグＭＯ）
水酸化マグネシウム（３）： ステアリン酸処理（協和化学工業製 キスマ５Ａ）
水酸化マグネシウム（４）： オレイン酸処理（協和化学工業製 キスマ５Ｂ）
水酸化マグネシウム（５）： シランカップリング処理（神島化学工業製 マグシーズＳ３）

EVA: Ethylene vinyl acetate copolymer resin
(Made by Tosoh MFR = 1.5, containing 20% vinyl acetate)
Magnesium hydroxide (1): Phosphate treatment (Kisuma 5J, Kyowa Chemical)
Magnesium hydroxide (2): No treatment (Fine Mug MO manufactured by TMG)
Magnesium hydroxide (3): stearic acid treatment (Kisuma 5A, manufactured by Kyowa Chemical Industry)
Magnesium hydroxide (4): Oleic acid treatment (Kyowa Chemical Industry Kisuma 5B)
Magnesium hydroxide (5): Silane coupling treatment (Magsees S3, manufactured by Kamishima Chemical Industries)

  As can be seen from Table 1, not only the untreated product, but also the stearic acid and oleic acid treated products do not improve the colorability. In addition, the silane coupling material can improve the colorability, but the foaming property is improved. In other words, it can be seen that by using magnesium hydroxide surface-treated with a phosphate ester, a sheet having good foamability can be obtained without coloring after foaming.

  According to the present invention, since an olefinic foamable resin composition and a foamed sheet excellent in foamability can be obtained by suppressing coloring after foaming, it can be widely used for wallpaper, leather, flooring and the like.

Claims (1)

A foamable resin composition comprising 2 to 10 parts by weight of an azo-based chemical foaming agent and 2 to 50 parts by weight of magnesium hydroxide whose surface is subjected to phosphoric acid ester treatment with respect to 100 parts by weight of an ethylene-vinyl acetate copolymer resin. Wallpapers that are molded .