JPH05200889A - Foam cushioning body and its manufacture - Google Patents

Abstract

PURPOSE:To manufacture a cushioning material of superior biodegradable properties easily to be decomposed by microbes in the natural environment and cushioning properties by bonding and solidifying foam polystyrene beads by a water foaming urethane bonding agent. CONSTITUTION:Primary foam polystyrene beads composed during the process in the middle of manufacturing foam polystyrene beads, particularly foam polystyrene heretofore available, are used for a cushion releaxing body represented by a packaging material and a transportation cushioning material are used. A desired foam cushioning body is manufactured from said beads by selectively using a specified bonding agent such as a water foaming urethane bonding agent and bonding and solidifying foam polystyrene beads. As for the foam polystyrene beads, regular beads of l-8mm diameter, preferably of approximately 3-5mm, are used, and their expansion ratio is approximately 40-80 and apparent density is approximately 0.025-0.012g/cm<3>. For the water foaming urethane bonding agent, for example, an organic polyisocyanae compound is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock absorber represented by a packaging material and a cushioning material for transportation.

[0002]

2. Description of the Related Art Polystyrene resin is mixed with a volatile liquid as a foaming agent, and primary expansion is performed at a temperature of 90 to 110 ° C. to obtain primary expanded polystyrene beads. In this case, the volatile liquid hardly dissolves polystyrene resin,
In addition, the boiling point of the polystyrene resin should be lower than or equal to the softening point of polystyrene resin, and hydrocarbons such as propane, butane, pentane, hexane, heptane, alcohols, esters, ethers, ketones, halogenated hydrocarbons, etc. Is used.

Subsequently, the primary expanded polystyrene beads are put into a mold and directly blown with steam, put in a shell mode with holes, and heated, or heated at a high frequency to cause secondary expansion. Then, the expanded polystyrene beads are heat-fused to each other and molded. The temperature in this case is 100 to 130 ° C. Moldability is good when the expansion ratio is 10 to 30 times (volume) in the primary expansion and 20 to 60 times (volume) in the secondary expansion.

Expanded polystyrene resin is used as a foamable synthetic resin container, packaging material, and cushioning material for transportation of 200,000 tons per year.
It has been used over.

In the conventional technique, polystyrene resin mixed with a volatile liquid as a foaming agent is pre-expanded at a temperature of 90 to 110 ° C. to obtain primary expanded polystyrene beads. Immediately, it is left in a well-ventilated silo for 12 to 24 hours to allow air to enter the bubbles of the foamed granules and at the same time to dry the foamed granules. At this time, the foaming agent should not be completely evaporated by being left unattended. Then, the primary expanded polystyrene beads are put into a molding die and directly blown with steam at a temperature of 130 ° C. for secondary expansion, and the expanded polystyrene beads are heat-bonded to each other for molding. Mainstream. Therefore, the molding die needs to be equipped with a pressure resistance against steam at a temperature of 130 ° C. and a heating / cooling cycle that can withstand continuous use.

Most of the synthetic plastics represented by expanded polystyrene resin are not decomposed by microorganisms in the natural environment, and a large amount of discarded plastic products retain their original shape forever without spoiling. , Has become the target of pollution.

[0007]

The problem to be solved by the present invention is a polystyrene foam, which is biodegradable, that is, it is easily decomposed by microorganisms in a natural environment, and has a cushioning effect. It is to develop new materials.

[0008]

This problem is solved by adhering and solidifying expanded polystyrene beads with a water-foamable urethane adhesive.

[0009]

In the present invention, expanded polystyrene beads, particularly preferably primary expanded polystyrene beads produced in the process of manufacturing conventional expanded polystyrene, are used, which are water-expandable urethane adhesives. The specified adhesive is specifically selected and used, and the basic principle is to bond and solidify the expanded polystyrene beads with the specified adhesive. And, more specifically, by using such a combination, since the specified adhesive is used and the expandable polystyrene beads are used, the degradability by microorganisms is greatly improved, and even in the natural environment, the microorganisms are decomposed. As a result, the expanded polystyrene beads are easily disintegrated, and the disposal property is remarkably improved. Moreover, the original cushioning effect of expanded polystyrene is hardly impaired.

Further, the following excellent effects are exhibited. For example, when the primary expanded polystyrene beads are used as the expanded polystyrene beads, the beads are adhered not by heat fusion between the expanded polystyrene beads by the conventional secondary expansion but by the urethane adhesive. Since the foamed particles are adhesively molded in this manner, the time for leaving the primary expanded polystyrene beads can be extended without being restricted by the secondary expansion. In addition, since the molding die does not use high-temperature steam, it does not need pressure resistance and does not require heating / cooling cycle equipment.

The expanded polystyrene beads used in the present invention are usually those having a diameter of about 1 to 8 mm, preferably about 3 to 5 mm. All that is known is used. The expansion ratio is preferably 40 to 80, but the apparent density is 0.025 to 0.012 g / c.
It is about m ³ .

The following are used as the water-foamable urethane-based adhesive used in the present invention.

The water-foamable polyisocyanate resin used in the present invention is an organic polyisocyanate compound containing two or more isocyanate groups in the molecule and / or its isocyanate group-terminated prepolymer and dialkoxylate monoalkylamine, Obtained from the reaction with one or more polyoxyalkylene addition higher aliphatic amine derivatives represented by trialkoxylate monoalkyldiamines, dialkoxylate monoalkylamides and trialkoxylate monoalkylamide amines.

Examples of the organic polyisocyanate compound for the resin include tolylene diisocyanate, xylylene diisocyanate, naphthylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, biphenylene diisocyanate, diphenyl ether diisocyanate having two or more functional groups. Examples thereof include trisine diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and the like. These isocyanate derivatives and the similar compounds can be used alone or as a mixture of two or more kinds.

The isocyanate group-terminated prepolymer is also obtained by reacting an organic polyisocyanate compound with a polyol having active hydrogen. As the polyol having active hydrogen, all polyols having at least two or more hydroxyl groups in one molecule can be used, but typical ones are polyester polyol, polyether polyol, epoxy polyol and the like. It is also possible to use a combination of two or more polyols.

Examples of polyester polyols include ethylene glycol, diethylene glycol, triethylene glycol 1,2-propylene glycol, trimethylene glycol, 1,3-butylene glycol,
One or more compounds having at least two hydroxyl groups such as tetramethylene glycol, hexamethylene glycol, decamethylene glycol, glycerin, trimethylolpropane, pentaerythritol and sorbitol, and malonic acid, maleic acid and succinic acid. Acid, adipic acid, tartaric acid, sebacic acid, oxalic acid, phthalic acid, terephthalic acid, azelaic acid, trimellitic acid and the like, one or more compounds having at least two carboxyl groups are used, and known compounds It can be manufactured by a method. Also included are lactone-based polyester polyols obtained by ring-opening polymerization of monomers having lactones typified by caprolactone and valerolactone.

Examples of the polyether polyol include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, trimethylene glycol, 1,3-butylene glycol, tetramethylene glycol, glycerin, sorbitol,
Alkylene having 2 or more carbon atoms such as ethylene oxide, propylene oxide, butylene oxide and styrene oxide, using one or more compounds having at least two active hydrogens such as sucrose, bisphenol A and pentaerythritol as a polyol starting material. It is produced by addition-polymerizing one or more monomers such as oxide and epichlorohydrin by a known method.

In addition, these polyols having active hydrogen include R ₃ O (R ₄ O) _n H (R ₃ : alkyl group, R
₄ : alkylene group) molecular weight of 250 to 4000
Alkoxy polyalkylene glycols of are also included.

The polyoxyalkylene non-higher aliphatic amine derivative used in the present invention has the chemical formula (1):
It is shown by (2), (3) and (4).

[0020]

[Chemical 1]

[0021]

[Chemical 2]

[0022]

[Chemical 3]

[0023]

[Chemical 4]

However, in the formula, R, R ₁ , R ₂ , X ₁ , X ₂ ,
Y ₁ , Y ₂ , Y ₃ , Z ₁ , Z ₂ and n are as follows.

R: a linear or branched alkyl group or hydroxyalkyl group having an average carbon number of 8 to 40 (however, alkenyl group, hydroxyalkenyl group, phenyl group and those having an ether bond in the carbon chain are also included).

R _{1 is} hydrogen or a methyl group (however, hydrogen and a methyl group may be introduced randomly or in a block form).

R _{2 is} a linear or branched alkyl group or hydroxyalkyl group having an average carbon number of 7 to 39 (however, alkenyl group, hydroxyalkenyl group, phenyl group and those having an ether bond in the carbon chain are also included).

X ₁ , X ₂ , Y ₁ , Y ₂ , Y ₅ , Z ₁ , Z ₂ : 1
An integer from ~ 350

N is an integer of 2 or 3.

R in the chemical formulas (1) to (4) and the chemical formula (5)

[0031]

[Chemical 5]

The fatty acid residue of is a natural fatty acid residue of plant or animal origin. The plant-derived natural fatty acid residue, for example, obtained from corn oil, cottonseed oil, peanut oil, rapeseed oil, sesame oil, soybean oil, safflower oil, coconut oil, balm oil, balm kernel oil, etc. Is
Obtained from pork oil, beef tallow oil, sardine oil, herring oil, squid oil, sardine oil, whale oil, etc.

These fatty acid residues from animal and vegetable oils may be used alone or in admixture of two or more.

The following can be used as additives. For example, a catalyst, a foam stabilizer, and if necessary, a flame retardant, a viscosity modifier and the like can be mentioned.

Examples of the catalyst include tertiary amines such as dimethylethanolamine, triethylenediamine, tetramethylpropanediamine, tetramethylhexamethylenediamine and dimethylcyclohexylamine, and organic tin compounds such as stannas octoate and dibutyltin dilaurate. Examples thereof include alkoxylate aliphatic quaternary ammonium salt compounds that are said to be effective in promoting the curability of the organic polyisocyanate compound and water.

Examples of the foam stabilizer include various siloxane-polyalkylene oxide block copolymers, the selection of which is determined by the formulation. Examples of the flame retardant include trischloroethyl phosphate, trischloropropyl phosphate, tricrudyl phosphate, chlorinated paraffin and the like.

The water-foamable polyisocyanate resin used in the present invention is a hydrophilic polyisocyanate resin composition having a relatively low viscosity. For this reason, the resin composition of the present invention does not particularly require a viscosity modifier, but may be added and blended depending on the case. However, low-boiling point organic solvents such as acetic acid esters and ketones are not preferable from the viewpoints of deterioration of working environment and risk of ignition. Alkylene carbonates and phthalates have high boiling points and flash points, and are preferable as viscosity modifiers.

From the water-foamable polyisocyanate resin used in the present invention, foams having various properties can be obtained. That is, by changing the type of the organic polyisocyanate compound, or by directly modifying the organic polyisocyanate compound with a polyoxyalkylene addition higher aliphatic amine derivative which is a compound in the present invention, or a general-purpose polyether polyol, polyester By changing the types of modifiers for the production of prepolymers such as polyols and the structure and molecular weight of polyoxyalkylene-added higher aliphatic amine derivatives, from soft foams with elasticity to hard foams with rigidity Since the expansion ratio can be arbitrarily adjusted from several times to several tens of times, it is possible to provide the characteristics suitable for the use of the buffer material.

Further, the obtained water-foamable polyisocyanate resin is biodegradable by the soil burying method, although the degree of degradability varies depending on the type of modifier, the degree of modification, the type of organic polyisocyanate compound, etc. In the test, a weight change of 50% or more was observed in a few months, and the buffer material obtained using the water-foamable polyisocyanate resin of the present invention as a binder was prepared by using non-biodegradable expanded polystyrenes as one of the substrates Was also confirmed to have considerable biodegradability.

This water-foamable urethane adhesive is decomposed and assimilated by microorganisms in soil and water, incorporated into the natural material circulation system, and does not pollute the global environment. When they are discarded after use, when they are disposed of in landfills, they are partially decomposed and assimilated by microorganisms, incorporated into the natural material circulation system, and decomposed. It never happens.

In the present invention, the means for adhering and solidifying the expanded polystyrene beads is not particularly limited, and any means capable of adhering and solidifying the beads with the above adhesive may be used.
As a typical example, a means for applying an adhesive or a solvent solution thereof to the surface of the beads and pouring it into a mold to adhere the beads at the same time as molding can be exemplified. The amount of the adhesive used is usually 20 to 100, preferably 40 per 100 parts by weight of the beads.
It is about 60 parts by weight.

The cushioning material of the present invention is usually 1 kg at 10% compression strain.
It has a strength of about f / cm ² and a porosity of an apparent density of about 0.02 to 0.4 g / cm ³ , and therefore can be effectively used as it is as a cushioning material.

[0043]

【Example】

Example 1 As the expanded polystyrene beads, used were the raw material trade name “Stypolol” which was expanded 50 times at 100 ± 10 ° C. As an adhesive, an average molecular weight of 1,000
A polypropylene prepolymer having a residual isocyanate group NCO% of 5.6 obtained by reacting 2 mol of MDI with the polypropylene glycol of was used. Expanded polystyrene beads 1
To 0 part, 5 parts of the adhesive is mixed, poured into a mold, and 5 parts of water is injected. Apparent density 0.02g / cm after drying at 105 ℃
A foam buffer of ³ was obtained. The buffer properties are shown in Table 1. According to the mold resistance test of ASTM-G-21-70, remarkable bacterial growth was observed after 3 weeks.

[0044]

Example 2 As the expanded polystyrene resin, the same expanded polystyrene beads as in Example 1 were used. The adhesive has an average molecular weight of about 1 consisting of adipic acid and ethylene glycol.
A urethane prepolymer having a residual isocyanate group NCO% of 5.4 obtained by reacting 000 polyester polyol with 2 times mole of MDI was used. To 10 parts of expanded polystyrene beads, 5 parts of an adhesive was mixed and poured into a mold to inject 5 parts of water. Apparent density after drying at 105 ℃ 0.02g /
A foam buffer of ³ cm ³ was obtained. The buffer properties of the buffer are shown in Table 1. According to the mold resistance test of ASTM-G-21-70, remarkable bacterial growth was observed after 3 weeks.

[0045]

Example 3 The same expanded polystyrene resin and adhesive as in Example 1 were used.

10 parts of expanded polystyrene beads are mixed with 3 parts of an adhesive, poured into a mold, and 5 parts of water is injected. 1
After drying at 05 ° C., a foaming buffer having an apparent density of 0.015 g / cm ³ was obtained. The buffer properties of the buffer are shown in Table 1.
According to the mold resistance test of ASTM-G-21-70,
Remarkable bacterial growth was observed after 3 weeks.

However, all parts in each of the above examples are parts by weight, and the mechanical strength was measured by static compression force and settability. Further, in Table 1, the characteristics of a conventional secondary expanded polystyrene (manufactured by Daiwa Paper Co., Ltd., having an expansion ratio of 50) are also shown for comparison.

[0048]

[Table 1]

[0049]

The foamed cushioning material of the present invention exhibits good mechanical strength, such as static compression strength, dynamic compression characteristics, and settability, after being formed into a molded product, and when it is discarded after use. Since the absorption and desorption of water and the assimilation action of microorganisms are combined, the strength is deteriorated and the shape is collapsed, so that the natural environment is not damaged unlike the conventional synthetic resin products.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kensuke Tani 440, Akiba-cho, Totsuka-ku, Yokohama, Kanagawa Nihon Polyurethane Industry Co., Ltd.

Claims (3)

[Claims] 1. A foamed buffer body in which expanded polystyrene beads are adhered and solidified with a water-foamable urethane adhesive. 2. The expanded polystyrene beads have a diameter of about 1
The foam cushioning body according to claim 1, which has a size of ˜8 mm. 3. A method for producing a foam cushioning body, which comprises bonding and solidifying expanded polystyrene beads with a water-foamable urethane adhesive.