JPH02270538A - Manufacture of foam - Google Patents

Abstract

PURPOSE:To strongly bond and fix foamed layer to polyolefin-based resin insert by a method wherein the polyolefin-based resin insert is coated with adhesive, which consists of compound having isocyanate group and halogenating agent, glued by synthetic resin and finally high-frequency-heated so as to expand the synthetic resin in order to provide foamed layer. CONSTITUTION:By gluing synthetic resin to polyolefin-based resin insert coated with adhesive, which consists of compound having isocyanate group and halogenating agent, the halogen in the halogenating agent halogenates non-polar polyolefin in the insert and, at the same time, polyurethane in the adhesive, resulting in making the intermolecular forces between the polyolefin and the polyurethane when high frequency heating is applied to the resin insert, to which the synthetic resin glued, said synthetic resin expands, resulting in forming foamed layer. By the blowing pressure at this time, the bonding strength between the insert and the foamed layer is improved all the more through the adhesive.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a foamed product by attaching a foamed layer to a polyolefin resin insert.
[Prior art and problems to be solved by the invention] Conventionally, a foamed layer of synthetic resin such as PVC (polyvinyl chloride) was attached to a resin insert made of polyolefin such as polypropylene (PP) or polyethylene (PE). Foams made of these materials are known.

When manufacturing this foam, for example, in addition to the resin insert, a foam layer is formed by reacting a synthetic resin such as PVC with a foaming agent, and this foam layer is bonded and fixed to the insert using an adhesive. .

However, the polyolefin resin inserts generally have poor adhesion and have low adhesive strength between the resin inner and the foam layer. Conventionally, the adhesive is applied after the resin insert is surface-treated with a chloroprene rubber-based plater. The adhesive is applied after applying a corona discharge treatment to the resin insert.

An object of the present invention is to provide a method for producing a foam that can firmly adhere and fix a foam layer to a polyolefin resin insert through simple steps.

[Means for Solving the Problems] Therefore, in order to achieve the above-mentioned object, the present invention applies an adhesive consisting of a compound having an isocyanate group and a halogenating agent to a polyolefin resin insert, and then attaches a synthetic resin to the polyolefin resin insert. The gist of this invention is a method for producing a foamed body in which the same synthetic resin is foamed by high-frequency heating to provide a foamed layer.

[Detailed Description of Means] The compound having an isocyanate group used in the production method of the present invention is a polyurethane having an isocyanate group obtained by reacting a polyol with an excess amount of polyisocyanate. Polyurethanes having isocyanate groups consisting of amines and polyisocyanates are preferred. And the molar ratio of polyol:triethanolamine is 1:0.0
5 to 2.0, and the molar ratio of hydroxyl group to isocyanate group is preferably in the range of t:t, S to 7. The adhesive contains 0.00 parts by weight (solid content) of the compound having an isocyanate group and 0.00 parts by weight of other halogen agents.
It is obtained by adding 2 to 20 parts by weight and, if necessary, a solvent.

As the polyol, polypropylene glycol,
A compound with propylene oxide added to glycerin,
Examples include compounds in which propylene oxide is added to sucrose. The polypropylene glycol preferably has a number average molecular weight in the range of 800 to 6,000.

The amine is triethanolamine, and a crosslinking reaction occurs with monoethanolamine and jetanolamine.
It is unsuitable because polyurethane gels.

Polyisocyanate is a compound having a plurality of isocyanate groups, and examples of aromatic polyisocyanates include tolylene diisocyanate (TDI), 1.5-naphthalene diisocyanate (NDI), xylylene diisocyanate (MD I), and 4.4'-diphenylmethane. Socyanate (MDI), 4.4", 4--)
As alicyclic polyisocyanates such as liphenylmethane triisocyanate (TPMI) and isophorone diisocyanate (IPDI), as aliphatic polyisocyanates such as 4,4'-methylenebis(cyclohexyl isocyanate) (H-MD I), hexahydroxylylene diisocyanate, etc. Examples include 1,6-hexamethylene diisocyanate.

The molar ratio of the polyol:triethanolamine is 1:
The ratio is preferably in the range of 0.05 to 2.0, and if this ratio is less than 0.05 or more than 2.0, the adhesion will be significantly reduced.

Further, the molar ratio of hydroxyl groups (-OH) in the polyol to isocyanate groups (-NGO) in the polyisocyanate is 1:1.5 to 7, and the isocyanate groups are blended in excess with respect to the hydroxyl groups.

When this ratio is less than 1.5 or more than 7, the adhesion strength decreases and adhesion may not occur.

The compound having an isocyanate group is synthesized, for example, by mixing the polyol, triethanolamine, and polyisocyanate, and reacting the mixture at 80° C. for 3 hours in a nitrogen gas atmosphere.

Next, as a halogenating agent, for example, alkyl hypohalide and t-butyl hypochloride (t-BHC) are used.
, sodium hypochlorite and potassium hypochlorite as hypohalites, N-bromosucciimide (NBSI), and isocyanuric acid trichloride (as compounds having -cONX- bonds (X is a halogen atom) in the molecule. TCIA),
Examples include dichlorinated cyanuric acid (DICIA), antimony pentafluoride, a mixed solution of sulfur fluoride and bromine, among which are alkyl hypohalides, hypohalites, or -C0NX- bonds in the molecule. Compounds having the following are preferred. .

The blending ratio of this halogenating agent is in the range of 0.002 to 20 parts by weight per 100 parts by weight of polyurethane. When the blending ratio is less than 0.002 parts by weight, the degree of halogenation is small, resulting in poor adhesion, and when it exceeds 20 parts by weight, the stability of the adhesive deteriorates.

In addition, solvents such as benzene, toluene, xylene,
Commonly used compounds include methyl acetate, ethyl acetate, isopropyl acetate, isobutyl acetate, acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, n-hexane, isooctane, and trichloroethylene.

The blending ratio of this solvent may be within a wide range of 3 to 95 parts by weight based on 100 parts by weight of the adhesive. If the blending ratio is less than 3 parts by weight, the solid content will be relatively high, increasing the viscosity and making coating work difficult, which will likely lead to a decrease in adhesive strength, while if it exceeds 95 parts by weight, the solid content will increase. As the proportion of the adhesive decreases, the film thickness of the adhesive becomes thinner, and the adhesive strength tends to decrease.

Examples of the resin insert used in the manufacturing method of the present invention include polyolefin resins such as PP and PE.

Examples of the synthetic resin include semi-rigid PVC, urethane resin, styrene resin, ethylene acid and resin (EVA), acrylonitrile-styrene copolymer resin (AS), and acrylic resin.

[Function] When an adhesive consisting of a compound having an isocyanate group and a halogenating agent is applied to a polyolefin resin insert and a synthetic resin is attached to this, the halogen in the halogenating agent has no polarity in the insert. By halogenating the polyolefin and halogenating the polyurethane in the adhesive, the intermolecular force between both increases.

When the 4M resin insert to which the synthetic resin is attached is subjected to high frequency heating, the synthetic resin foams to form a foam layer. It is presumed that the foaming pressure at this time further improves the adhesive strength between the insert and the foam layer due to the adhesive.

[Example] Hereinafter, an example embodying the method for manufacturing a foam of the present invention will be described.

(1) Synthesis of polyurethane First, polyol (PO), triethanolamine (TEA), and polyisocyanate (PI) shown in Table 1 below are used.
Each of the combinations ① to ② are mixed in trichlorethylene and reacted for 3 hours in an atmosphere of about 80 tons of nitrogen gas. As a result, seven types of polyurethane are synthesized. The composition of the polyurethane thus obtained was 83 solids.
%, trichlorethylene 17%.

Table-1 The abbreviations in Table-1 represent the following meanings.

・TG 1000, 2000.3000: Poly (triethylene glycol) with a number average molecular weight of 1000.2000.3000, respectively.PPG 1000,200
0.3000? Each number average molecular weight 1000.200
0.3000 polypropylene glycol/MDI: 4.4'-diphenylmethane diisocyanate/NDI: 1.5-naphthalene diisocyanate/XD
I: Xylylene diisocyanate/IPDI: Isophorone diisocyanate/TDI:) Lylene diisocyanate (2) Synthesis of adhesive Subsequently, a halogenating agent as shown in Table 2 is added to 100 parts by weight of the solid content of the polyurethane. -2 The abbreviations in Tables 2 above have the following meanings.

・t-BHC: t-butyl hypochloride ・NBSI
:N-Bromosuccinimide/TCIA, :Isocyanuric acid trichloride (3) By applying adhesive and pasting synthetic resin, Examples 1 to 6 and Comparative Examples were applied to both the front and back sides of a resin insert made of PP with a plate thickness of 2n. 1.2 each adhesive 80
After coating to ~100μm thickness, 0.4mm thick PVC
Apply the composition. In this example, the PVC composition includes 100 parts by weight of polyvinyl chloride with a degree of polymerization of 1900, 120 parts by weight of dioctyl phthalate, and 3 parts by weight of epoxidized soybean oil.
Parts by weight and dibutyltin dilaurate (stabilizer) 4.5
A mixture of parts by weight was used.

(4) Foaming The resin insert to which PVC is attached is air-dried at room temperature for about 10 minutes or with hot air at 120 to 150° C. for about 1 minute, and then pressure-molded while performing high-frequency heating. In this example, the molding conditions at this time are 1
27 while closing the mold with a mold closing pressure of 00 kg/crA.
After applying electricity at a megahertz frequency for 2 minutes, it was cooled under pressure for 10 minutes. In this way, even if no blowing agent is used, P
The vC is heated and foamed to form a foam layer with a thickness of about 2 mm on both sides of the resin insert, thereby completing the foam.

(5) Measurement of peel strength Examples 1 to 6 and Comparative Example 1 manufactured as described above
The peel strength of each foam was measured.

A 25n+ width foam was used in this measurement. The measurement results are shown in Table-3.

Table-3 In Table-3 above, * indicates that the foam layer has been destroyed, *
* indicates that the interface between the foam layer and the resin insert was destroyed.

As shown in Table 3, the blending ratio of halogenating agent in the adhesive is 0.0 parts by weight per 100 parts by weight of polyurethane.
In Comparative Example 1.2 where the amount was outside the range of 0.02 to 20 parts by weight, the adhesive gelled or the normal peel strength was 2.0.
1, and the interface between the foam layer and the resin insert was destroyed, whereas in this example, the normal peel strength was so high that the foam layer was destroyed (19,1~
21.8 kg/cm).

This is because the halogen in the halogenating agent halogenates the polyolefin in the PP, which is a non-polar resin insert, and also halogenates the polyurethane in the adhesive, increasing the intermolecular force between the two. Conceivable.

Furthermore, in this example, it is considered that the foaming pressure when forming the foam layer contributed to improving the adhesive strength between the resin insert and the foam layer.

Therefore, according to the foam manufacturing method of this example, it is possible not only to firmly adhere and fix the foam layer to the polyolefin resin insert, which is difficult to adhere to, without using a primer. Since this can be carried out simultaneously with the molding of the foam layer, the manufacturing process can also be simplified.

[Effects of the Invention] As detailed above, according to the present invention, an excellent effect is achieved in that a foam layer can be firmly adhesively fixed to a polyolefin resin insert through a simple process.

Patent applicant: Toyoda Gosei Co., Ltd.

Claims (1)

[Claims] 1. After applying an adhesive consisting of a compound having an isocyanate group and a halogenating agent to a polyolefin resin insert, a synthetic resin is attached, and the synthetic resin is foamed by high-frequency heating to form a foam layer. A method for producing a foam, characterized by: