JP2003335884A - Luminous polyolefin foam and its preparation process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a luminous polyolefin foam which develops color in the dark and emits afterglow for ≥1 hr after lights are turned off, and its preparation process. <P>SOLUTION: In the preparation process, a blend, prepared by blending dinitrosopentamethylenetetramine, a crosslinking agent and 2-20 pts.wt. luminous pigment containing 60-70% aluminum chloride, 20-30% strontium chloride and 1-5% antimony trioxide into a polyolefin resin, is filled in a mold inside a press, sealed under pressure, heated for a predetermined time to decompose the foaming agent and subsequently depressurized to obtain the foam. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphorescent polyolefin foam used for toys, catalogs and the like, and a method for producing the same.

[0002]

2. Description of the Related Art Polyolefin foam is excellent in heat insulation, weather resistance, elasticity, etc., and is a heat insulating material, joint material for civil engineering and construction, toys,
Used in packaging materials, sports equipment, etc. As a method for coloring the polyolefin foam, a method of kneading a polyolefin resin with a pigment and an organic foaming agent to heat foam for a long time, or pressurizing one-stage foaming, two-stage foaming (Japanese Patent Publication No. 2-426).
In Japanese Patent Laid-Open No. 49), a method of heat-foaming in a block shape is generally used. In a bright place, color can be identified, but in a dark place, presence of foam and color cannot be identified.

Recently, the Applicant has found that phosphorescent zinc sulfide (Zn)
A phosphorescent polyolefin foam containing a phosphorescent pigment containing S: Cu) as a main component and a method for producing the same have been proposed (Japanese Patent Laid-Open No. 2000-336201). However, the phosphorescent fluorescent powder used in the present invention can store light and emit light, but the emission time is only about 1 to 2 hours, the chemical stability is low, the water resistance is inferior, and it easily ages. Under the conditions, there are drawbacks such that the light emitting ability is drastically reduced and the service life is short.

[0004]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to solve the above-mentioned drawbacks of the prior art, to develop color in a dark place,
It is an object of the present invention to provide a phosphorescent polyolefin foam which has a high luminescence intensity, a long luminescence time, and excellent water resistance, and is useful for toys, guide signs, advertising products and the like, and a production thereof.

[0005]

In order to achieve the above-mentioned object, the phosphorescent polyolefin foam of the present invention is characterized in that a phosphorescent pigment containing aluminum chloride, strontium chloride and antimony trioxide is mixed with a polyolefin resin. To do.

In the present invention, the luminous pigment is aluminum chloride 60-70%, strontium chloride 20-30.
%, And a mixture containing 1 to 5% of antimony trioxide is preferable, and if it is out of this range, the emission intensity and emission time will be poor.

The method for producing a phosphorescent polyolefin foam of the present invention comprises a polyolefin resin, a foaming agent, a crosslinking agent, and
It is characterized in that a phosphorescent pigment containing aluminum chloride, strontium chloride and antimony trioxide is mixed and heated and foamed.

In the production method of the present invention, the phosphorescent pigment is
Aluminum chloride 60-70%, Strontium chloride 2
A mixture containing 0 to 30% and antimony trioxide 1 to 5% is preferable, and if it is out of this range, the emission intensity and the emission time are inferior.

In the production method of the present invention, it is preferable that the foaming agent is dinitrosopentamethylenetetramine, because the residue has no yellowish tint and produces vivid color.

The phosphorescent pigment used in the present invention is
By containing the element “Sb”, it has a function of suppressing grain growth of crystals during firing. As a result, since the particles of a minute unit (nm unit) have a light-storing property, a light-storing pigment composed of fine particles can be used, the compatibility with a resin and a foaming agent is excellent, and the bubbles of the resulting foam are uniformly fine.

In the present invention, the polyolefin resin 10
It is preferable to add 2 to 20 parts by weight of such a phosphorescent pigment to 0 parts by weight. If the amount of the luminous pigment is less than 2 parts by weight, the coloring phenomenon is weak, and if it exceeds 20 parts by weight, the foaming is adversely affected.

The foaming method applied in the production method of the present invention includes non-crosslinking extrusion foaming, long sheet foaming or block foaming by chemical crosslinking or electron beam crosslinking, and is not particularly limited, but the following foaming method is preferable. .

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the method for producing a phosphorescent polyolefin foam according to the present invention will be specifically described below.

(Pressurized one-step foaming) A polyolefin is mixed with a phosphorescent pigment, a foaming agent, a foaming auxiliary agent, a cross-linking agent and, if necessary, a filler, which is mixed by a heated mixing roll, a pressure kneader, an extruder or the like. To do. The mixture is filled in a mold, which is sealed under pressure to give 120-180
The foaming agent and the cross-linking agent are decomposed by heating at 10 ° C., preferably 130 to 170 ° C. for 10 to 50 minutes, preferably 25 to 40 minutes, and after depressurization, the foam is taken out.

(Two-stage foaming method) Alternatively, a moldable composition is filled with a moldable composition, and the mold is sealed under pressure.
It is preferably heated at 130 to 170 ° C. for 10 to 50 minutes, preferably 25 to 40 minutes to partially decompose the foaming agent and the cross-linking agent, and decompressed to remove the intermediate foam from the mold, and then the final product. The above-mentioned intermediate foam is put into a mold which is not hermetically sealed and has a heating medium passing through a jacket provided in the mold to 140 to 200 ° C, preferably 1
50 to 170 ° C., 10 to 100 minutes, preferably 20
By heating for 80 minutes, the remaining foaming agent is decomposed and foamed, and a foam having uniform physical properties is obtained.

The polyolefin resin used in the present invention is, for example, low density polyethylene (LDPE),
Linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), ethylene-based resins such as ethylene / vinyl acetate copolymer, and propylene homopolymer, propylene / α-olefin random copolymer, propylene / α- Examples thereof include propylene-based resins such as olefin block copolymers, and so-called general-purpose polyolefin-based resins such as other olefin-based polymers and copolymer resins.

The foaming agent which can be used in the present invention is a chemical foaming agent having a decomposition temperature higher than the melting temperature of the polyethylene resin, such as azodicarbonamide of an azo compound.
Barium azodicarboxylate, etc .; nitroso compounds, dinitrosomethylene pentatetramine, trinitrotrimethyltriamine, etc .; hydrazide compounds, p, p
'-Oxybisbenzenesulfonyl hizorazide, etc .; sulfonylsemicarbazide compounds p, p'-Oxybisbenzenesulfonylsemicarbazide, toluenesulfonylsemicarbazide, etc. Notably, the brightness is low with the use of azodicarbonamide.

In the present invention, the cross-linking agent has a decomposition temperature in the resin which is at least higher than the flow initiation temperature of the resin, and is decomposed by heating to generate free radicals and cross-link between the molecules or within the molecule. Organic peroxides that are radical generators that form bonds, such as dicumyl peroxide, 1,1-ditertiary butylperoxy-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-diter Tert-butyl peroxyhexane, 2,5-dimethyl-2,5-ditertiary butyl peroxyhexyne, α, α-ditertiary butyl peroxyisopropylbenzene, tert-butyl peroxyketone, tert-butyl peroxybenzoate, etc. However, depending on the resin used at that time The optimum organic peroxide must be selected.

In the present invention, a foaming aid can be added depending on the kind of the foaming agent. Examples of the foaming aid include compounds containing urea as a main component, metal oxides such as zinc oxide and lead oxide, compounds containing salicylic acid and stearic acid as main components, that is, higher fatty acids or metal compounds of higher fatty acids.

In the present invention, for the purpose of improving the physical properties of the composition to be used or lowering the price, compounding agents (fillers) which do not significantly adversely affect the cross-linking, such as zinc oxide, titanium oxide, calcium oxide, and oxidation. magnesium,
Metal oxides such as silicon oxide, carbonates such as magnesium carbonate and calcium carbonate, fibrous substances such as pulp, various dyes and pigments, and other commonly used rubber compounding agents can be added as necessary.

The afterglow brightness of the phosphorescent foam obtained in the present invention is measured by the following method.

After shutting off the light for 24 hours, it is irradiated with a 15 W desk fluorescent lamp from a distance of 40 cm for 20 minutes. afterwards,
The afterglow luminance is measured with a luminance meter (LS-100 luminance meter, manufactured by Minolta Co., Ltd.) from a distance of 400 mm.

[0023]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.

Example 1 Ethylene vinyl acetate copolymer (trade name: Novatec L
V-440, vinyl acetate content 15%, melt flow rate 2.0 g / 10 min, Mitsubishi Chemical Corporation 100 parts by weight, phosphorescent pigment (trade name: Easy Bright, composition: aluminum chloride 60-70%, chloride) Strontium 20 ~
30%, antimony trioxide 1-5%, made by Easy Bright Co., Ltd.) 5.0 parts by weight, dinitrosomethylene pentatetramine 4.0 parts by weight, urea foaming aid 4.0 parts by weight, dicumyl peroxide. 0.7 parts by weight of the composition was kneaded with a mixing roll at 85 ° C., and a mold (19 × 155 × 155 m in a press heated to 150 ° C.) was kneaded.
m) was filled with the above kneaded product, heated under pressure for 40 minutes and then depressurized to obtain a foam.

The resulting foam has an apparent density of 60 kg /
It was m ³ .

When the afterglow brightness was measured, it showed a brightness of ² mcd / m ² even after 90 minutes, and the foam could be confirmed even in the dark.

Example 2 In Example 1, the resin was low density polyethylene (trade name: Novatec YF-30, melt flow rate 1.
1 g / 10 min, density 0.920 g / cm ³ , manufactured by Mitsubishi Chemical Co., Ltd.), except that the composition and foaming conditions were the same as in Example 1 to obtain a foam.

The apparent density of the resulting foam is 61 kg /
The brightness after 90 minutes of m ³ was ² mcd / m ² , and the foam could be confirmed even in the dark.

Comparative Example 1 In Example 1, the phosphorescent pigment was used as a component but did not contain aluminum chloride, strontium chloride, or antimony trioxide (trade name: GSS, main components ZnS, Cu, manufactured by Nemoto Special Chemical Co., Ltd.). A foam was obtained by foaming under the same composition and under the same conditions as in Example 1 except for the above.

The apparent density of the resulting foam is 60 kg /
The brightness after 60 minutes of m ³ was 1 mcd / m ² , and the foam could not be confirmed in the dark.

[0031]

As described above, according to the present invention, it is possible to produce a phosphorescent polyolefin foam by using a phosphorescent pigment which is a mixture containing aluminum chloride, strontium chloride and antimony trioxide, thereby producing a dark place. The afterglow time after turning off the electricity is 1 hour or more, the compatibility of the phosphorescent pigment with the resin and the foaming agent is excellent, and the emission intensity, the emission time and the water resistance are excellent, and the toys, the induction markers, It is useful for advertising goods.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09K 11/00 C09K 11/00 C 11/08 11/08 J 11/55 CPF 11/55 CPF 11/64 CPM 11/64 CPM 11/75 CPB 11/75 CPB F Term (Reference) 2C150 FB16 FB43 FB55 4F074 AA16 AA17 AA22 AC11 AC15 AC17 BA13 BA16 BA17 BA18 BA19 BA20 BB02 BB10 CA24 CA30 CC03Y CC04Y DA02 DA45 DA47 DA08 X38A001 XA51 YA51 4J002 BB011 BB031 BB061 BB121 BB141 BP031 DD076 DE126 EK038 EK058 EK068 EQ017 EQ027 ES007 FD010 FD096 FD148 FD150 FD206 FD327 GC00 GN00 GT00

Claims (5)

[Claims] 1. A phosphorescent polyolefin foam comprising a polyolefin resin mixed with a phosphorescent pigment containing aluminum chloride, strontium chloride and antimony trioxide. 2. The phosphorescent pigment is aluminum chloride 60 to 7
The phosphorescent polyolefin foam according to claim 1, which is a mixture containing 0%, strontium chloride 20 to 30%, and antimony trioxide 1 to 5%. 3. A method for producing a phosphorescent polyolefin foam, which comprises mixing a polyolefin resin with a foaming agent, a cross-linking agent, and a phosphorescent pigment containing aluminum chloride, strontium chloride, and antimony trioxide, and heat-foaming the mixture. 4. The phosphorescent pigment is aluminum chloride 60 to 7
The production method according to claim 3, which is a mixture containing 0%, 20 to 30% strontium chloride, and 1 to 5% antimony trioxide. 5. The method according to claim 3, wherein the foaming agent is dinitrosopentamethylenetetramine.