JPH05246466A - Packing member and styrene adhesive - Google Patents

Abstract

PURPOSE:To make a packing member recyclable, and improve the adherent strength by a method wherein a styrene adhesive, which contains a plasticizer by a specified rate to a low mol ecular weight polystyrene, is used, and a packing member is constituted of a laminated body for which styrene foams are put together. CONSTITUTION:The title packing member is constituted in such a manner that a styrene paper 10 and block shaped styrene expanded bodies 20 are adhered by an adhesive 30. In this case, as the adhesive 30, a styrene adhesive, which contains 5-40 pts.wt. of a plasticizer based on 100 pts.wt. of a low molecular weight polystyrene, is used. Then, the packing member is constituted of a laminated body for which the styrene foams are put together. Also, as the plasticizer, a phthalic ester plasticizer such as dibutyl phthalate, etc., and others are used. By this method, a styrene packing member and adhesive, which are recyclable and superior in adherent strength, are obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging material and a styrene adhesive, and more particularly to a recyclable packaging material and a styrene adhesive.

[0002]

2. Description of the Related Art In recent years, from the viewpoints of resource saving and environmental pollution prevention, recycling of various daily necessities, especially packaging or packaging members, has been studied. As one of these packaging members, the use of styrene foam together with cardboard packaging as a cushioning material is widely used in the fields of various industrial materials such as electric equipment and office equipment, food products, etc. ..

When used as such a cushioning material, a styrene foam is generally used as a molded product or a cut product which is attached to a cardboard board as a laminate. In order to reuse the cardboard board, it is first necessary to separate the styrene foam and the cardboard board. However, it is difficult to separate the strongly bonded laminate into two materials without adhering the other material, and the work is complicated. At present, there is no known adhesive suitable for recycling.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a styrenic packaging member and an adhesive which can be recycled and have excellent adhesive strength.

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to a laminated body in which styrene foams are bonded together by using a styrene-based adhesive containing 5 to 40 parts by weight of a plasticizer to 100 parts by weight of low molecular weight polystyrene. The present invention provides a packaging member.

The present invention also relates to low molecular weight polystyrene 1
The present invention provides a styrene-based adhesive containing 5 to 40 parts by weight of a plasticizer with respect to 00 parts by weight.

The packaging member of the present invention comprises a laminated body which is laminated by using a styrene adhesive. As the low molecular weight polystyrene constituting the styrene adhesive, polystyrene having an average molecular weight of about 350 to 2,300 and a softening temperature of 50 to 150 ° C. is preferable, and a softening temperature of 75 to 125 ° C. is particularly preferable.
Are especially preferred.

Low molecular weight polystyrene has an average molecular weight of about 3
If it is less than 50, the adhesive strength is insufficient, while if it is 2, 3
If it exceeds 00, the softening temperature becomes high and the viscosity becomes high, so that the workability is deteriorated, which is not preferable. Also, the softening temperature is 50 ° C.
If it is less than 150 ° C., it is inconvenient to handle, and if it exceeds 150 ° C., the styrene foam to be bonded may be deformed or secondary foaming may occur, which is not preferable.

As such low molecular weight polystyrene, those commercially available as additives such as plasticizers of various polymers such as synthetic rubber, polystyrene and vinyl chloride, adhesiveness imparting agents and reinforcing agents can be used. Commercially available low molecular weight polystyrenes include, for example, Piccolast.
ic "A" series, "D" series, and "E" series (Hercules).

Conventionally, when the packaging member as shown in FIG. 1 is produced, when the cardboard plate 10 and the styrene foam 20 are attached to each other, the adhesive 30 is usually 1
A hot-melt adhesive such as a polyamide-based or polyolefin-based hot-melt adhesive heated to about 50 ° C. has been used. But,
When using styrene foam, such as styrene paper or styrene block slices, in place of the cardboard board,
Since the normal softening agent has a too high softening temperature, there is a problem that the styrene foam is deformed or causes secondary foaming. Therefore, in the present invention, it is conceived to use an adhesive having a low softening temperature, and to facilitate the recycling use of the packaging member, to use no foreign matter as a raw material. It uses polystyrene as an adhesive.

Next, the styrenic adhesive of the present invention contains 5 parts by weight of a plasticizer based on 100 parts by weight of the low molecular weight polystyrene.
40 parts by weight, preferably 10 to 20 parts by weight. Addition of a plasticizer improves the fragile and hard properties of low-molecular-weight polystyrene with insufficient adhesive strength, and makes it possible to obtain a packaging member having excellent adhesive strength and impact resistance. When the content of the plasticizer is less than 5 parts by weight, the plasticizing effect is insufficient, the adhesive strength is insufficient, and only a brittle and impact resistant packaging member can be obtained. On the other hand, if the content of the plasticizer exceeds 40 parts by weight, the plasticizer moves from the adhesive to the styrene foam, plasticizes the styrene foam, and reduces the adhesive strength, which is not preferable.

In the present invention, examples of the plasticizer include dibutyl phthalate, diisobutyl phthalate, di-n-octyl phthalate, di-2-ethylhexyl phthalate (DOP), didodecyl phthalate, butylbenzyl phthalate, diisodecyl phthalate, dinonyl. Phthalates such as phthalate, diisononyl phthalate, octyl capryl phthalate, dicyclohexyl phthalate, dimethyl glycol phthalate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl ethyl glycolate; methyl acetyl ricinoleate; Di-2-ethylhexyl adipate (DOA), di-n-octyl adipate, dibutyl sebacate, di-2-ethylhexyl sebacate, di-2-e Hexyl azelate, glycerol triacetate, glycerol sebacate, diisodecyl succinate, diisodecyl adipate, fatty ester plasticizers such as succinic acid mixed alkyl esters; tributyl phosphate, triphenyl phosphate (T
PP), tricresyl phosphate (TCP), trixylenyl phosphate, trichloroethyl phosphate, tri-2-ethylhexyl phosphate, triethyl phosphate, diphenyl cresyl phosphate, monophenyl dicresyl phosphate, dicresyl monoxylenyl phosphate, mono Cresyl dixylenyl phosphate Aryl alkyl phosphate, diphenyl monoxylenyl phosphate, monophenyl dixylenyl phosphate and other phosphate ester plasticizers; trimellitic acid tri-2-ethylhexyl ester and other trimellitic ester plasticizers Epoxy plasticizers such as epoxidized soybean oil and epoxidized linseed oil; Polyvinyl chloride such as polymer plasticizers such as polyester plasticizers such as polypropylene adipate It can be used Le resin for plasticizer.

It is also possible to use an aliphatic ester generally known as a lubricant for vinyl chloride resins, such as butyl stearate and butyl oleate. For example,
Butyl stearate has excellent compatibility with low molecular weight polystyrene, can improve its fluidity and can exert a plasticizing effect, and is included in the plasticizer in the present invention.

According to the present invention, 5 to 40 parts by weight of 100 parts by weight of low molecular weight polystyrene is melted by heating, and it has transparency even after cooling and loses the fragility peculiar to low molecular weight polystyrene resin. Can be used as a plasticizer. These plasticizers can be used alone or in admixture of two or more.

By containing these plasticizers, the low molecular weight polystyrene changes from a fragile and hard resin to a semi-hard or soft resin, and when used as an adhesive, a packing member having sufficient adhesive strength is obtained. Can be provided.

The styrene-based adhesive of the present invention may contain additives such as a flame retardant, a combustion accelerator and a colorant, if necessary, in addition to the low molecular weight polystyrene and the plasticizer. The styrene-based adhesive is formed by kneading a low-molecular weight polystyrene, a predetermined amount of a plasticizer and other additives at a temperature higher than the softening temperature of the low-molecular weight polystyrene in an extruder, for example, to form a pellet, and a hot-melt roll. Can be used in coaters.

As described above, the styrene-based adhesive of the present invention has a low viscosity and a low melting point and thus is excellent in workability. Since it contains an appropriate plasticizer, it is flexible and has excellent adhesive strength. Deform those materials as an adhesive for packaging members,
It can be attached without damage and is suitable for recycling.

Next, in the present invention, as the styrene foam, for example, beads or pellets of expandable polystyrene obtained by blending polystyrene with a blowing agent such as butane, pentane or hexane of several% are put in an extruder. A so-called styrene paper obtained by extrusion molding can be mentioned.

Further, as another styrene foam, for example, beads or pellets of the expandable polystyrene are directly or prefoamed and placed in a mold and heated to 20 to
Examples include molded products obtained by expanding 110 times, cut products thereof, and sliced products.

The laminated body constituting the packaging member of the present invention is, for example, a laminated body as shown in FIG. 1 in which the above-mentioned styrene paper and a block-shaped styrene foam generally used as a cushioning material are bonded together. Styrene paper 1
0, block-shaped styrene foam 20), a large block is sliced, for example, a sheet foam having a thickness of 3 mm and a cut product obtained by cutting the large block are bonded together, the cut products are bonded together, and the molded products are bonded together. A laminated body in which a plurality of styrene foams such as a laminate are stuck together can be mentioned.

In the production of the laminate in the present invention, the styrene-based adhesive is melted at a temperature not lower than the softening temperature of low-molecular-weight polystyrene, adhered to one side of the styrene-foam by a roll coater, etc. A laminated body can be created by laminating. The amount of the styrene-based adhesive attached is not particularly limited, and can be appropriately set by selecting the melting temperature, the amount of plasticizer, and the molecular weight.

The packaging member of the present invention has excellent adhesive strength between styrene foams, and since the material constituting the laminate is polystyrene and does not contain foreign matter, it is not necessary to separate and collect them by material. It is easy to recycle and can contribute to resource saving and environmental pollution prevention.

[0023]

EXAMPLES The present invention will be described in more detail with reference to the following examples. In addition, a part shows a weight part in an Example. Example 1 As a low molecular weight polystyrene, an average molecular weight of about 1040,
100 parts of polystyrene (Picolastic D125 manufactured by Hercules Co., Ltd.) having a glass transition temperature of 53 ° C. and 20 parts of DOA as a plasticizer were prepared and melt-mixed at 140 ° C. to prepare a styrene-based adhesive 1.

A commercially available 1.6 mm thick styrene paper and a cut product of expanded polystyrene block having a density of 16 kg / m ³ were prepared, and the adhesive 1 in a molten state was applied to the cut product and lightly pressed against the styrene paper. After about 30 minutes, an attempt was made to peel the twisted product by twisting it, but it was firmly bonded and the styrene paper was broken.

Example 2 As low-molecular-weight polystyrene, 100 parts of polystyrene having an average molecular weight of about 574 and a glass transition temperature of 32 ° C. (Picolastic A75 manufactured by Hercules), 100 parts of polystyrene used in Example 1, and 40 parts of DOA were used. 140 ° C
Were melt-mixed with each other to prepare a styrene-based adhesive 2. Similar to Example 1, a styrene paper and a cut product were attached and peeling was attempted, but the styrene paper was broken as in Example 1.

Example 3 As low molecular weight polystyrene, 100 parts of polystyrene used in Example 1 and a styrene-modified hydrogenated terpene resin [molecular weight 630, manufactured by Yasuhara Chemical Co., CREARON]
M-105, glass transition temperature 48 ° C.] 100 parts, D
40 parts of OA was melt mixed at 140 ° C. to prepare a styrene-based adhesive 3. When a peeling test was performed using this adhesive in the same manner as in Example 1, it was firmly bonded.

Comparative Example 1 A molten resin composition was prepared in the same manner as in Example 1 except that 20 parts of hydrogenated rapeseed oil was used in place of the DOA of Example 1. Using this resin composition as an adhesive, Example 1
When a peeling test was conducted in the same manner as above, it could not be easily peeled from the adhesive layer by a weak impact and used as an adhesive.

Comparative Example 2 When the amount of DOA used in Example 1 was changed to 2 parts to prepare a molten resin composition and the same test as in Example 1 was conducted, it was easily peeled from the adhesive.

Comparative Example 3 Styrene-modified hydrogenated terpene resin 100 used in Example 3
Part and 20 parts of DOA, a molten resin composition was prepared and tested in the same manner. As a result, delamination was easy.

[0030]

According to the present invention, it is possible to provide a packaging member which has excellent adhesive strength and is easy to recycle, and the present invention can contribute to resource saving and prevention of environmental pollution. Further, the present invention provides a styrene-based adhesive which is used for bonding styrene foams to each other, has excellent workability, does not cause deformation of the styrene foam, and does not cause secondary foaming, and has excellent adhesiveness. You can

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a laminated body constituting a packing member of the present invention.

[Explanation of symbols]

 10 Styrene Paper 20 Blocky Styrene Foam 30 Adhesive

Claims (2)

[Claims] 1. A packaging member comprising a laminate in which styrene foams are bonded together by using a styrene-based adhesive containing 5 to 40 parts by weight of a plasticizer with respect to 100 parts by weight of low molecular weight polystyrene. 2. A styrenic adhesive containing 5 to 40 parts by weight of a plasticizer with respect to 100 parts by weight of low molecular weight polystyrene.