JPS6023699B2 - Foam manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing olefin homopolymer or olefin copolymer foams.

Conventional methods for producing foams from emulsions of olefin homopolymers or olefin copolymers include dispersing expandable fine particles in an emulsion and applying it to a substrate, and dispersing air or other gases in the emulsion. There is a method of applying it to a base material and foaming it.

However, with conventional methods, the foaming process is extremely difficult, as the bubbles may burst during coating, forming aggregated bubbles, or gas may escape to the outside during foaming, especially when using methods that mechanically mix gas. It is necessary to gel and melt after foaming, and because the foam has good insulation properties, gelling and melting require a large amount of heat, so productivity is low, and it is a foam that should not be used in terms of physical properties. is difficult to manufacture. The present inventors have conducted various researches in order to solve the drawbacks of such conventional methods and produce excellent foams economically and with good workability. A foaming emulsion made by dispersing a thermally decomposable foaming agent, a decomposition accelerator, a filler, etc. is applied or printed on a base material, and the applied or printed foaming emulsion is heated and dried to remove moisture. After that, when foaming is performed, there is no generation of defective products due to work errors, etc., and the foam can be manufactured extremely efficiently and at low cost.Moreover, the resulting foam is resistant to mechanical, air, and thermal stress. It also has the ability to absorb acoustic energy, has low density, is lightweight, has special surface characteristics, is non-slip, has excellent squeezing properties, and has low combustion heat and does not produce smoke characteristic of plastics. They discovered that the present invention is suitable for wall materials, ceiling materials, furniture sheets, etc., and have completed the present invention.

That is, the present invention involves dispersing a thermally decomposable blowing agent, a decomposition accelerator, a filler, etc. in an emulsion of an olefin homopolymer or a Z olefin copolymer to obtain a foamable emulsion, and applying the foamable emulsion to a substrate. or printed, and the foamable emulsion coated or printed on the base material is heat-dried to remove moisture 2, and then foamed, mainly {11 Preparation of the above-mentioned specific foamable emulsion [2] A step of applying or printing the foamable emulsion on the Motomura; and 3) Heating the foamable emulsion applied or printed on the Motomura.
It consists of a simple process of drying to remove water and then foaming, and there is almost no defective product due to operational errors, and the foam can be manufactured extremely efficiently and at low cost.

Moreover, in the three steps of preparing a foamable emulsion, the present invention allows various changes in the types and blending ratios of the olefin homopolymer or olefin copolymer, thermally decomposable blowing agent, decomposition accelerator, filler, etc. or by changing the coating or printing amount in the process of applying or printing the foamable emulsion on the base layer, or by variously changing the foaming temperature, heating time, and other processing conditions in the foaming process. ,
Since the expansion ratio, physical properties, appearance, etc. of the obtained foam can be adjusted, it is possible to produce a foam having characteristics most suitable for its intended use and use. Such remarkable effects cannot be achieved by conventional methods such as those described above, and after coating or printing the specific foamable emulsion as described above on a substrate,
This can only be achieved by the method of the present invention, which involves heating and drying to remove water and then foaming.

The foamable emulsion used in the present invention has a viscosity of 500 to 2500 ratio P (at 2yo It is a foaming emulsion with a viscosity of approximately

In this way, it is necessary to add foaming agents, decomposition accelerators, fillers, etc. to the resin, which is the main component, and the use of such foaming agents, decomposition accelerators, fillers, etc. Emulsion coating and printing properties are improved, coating,
Printing operations can be carried out smoothly, and the foaming ratio can be easily adjusted, thereby making it easier to form excellent foams even on a variety of complex substrates. For example, even if only a blowing agent is added to an emulsion of an olefin homopolymer or an olefin copolymer, it is difficult to perform coating and printing operations smoothly, especially when the coating is applied to a thickness of 0.1 or more. After heating and drying, it is difficult to form a good high-quality foam on a complex substrate, such as a wavy surface condition, and the surface of the foam becomes uneven and rough, and it becomes sticky. remains, making it difficult to commercialize the foam. Examples of the olefin homopolymer or olefin copolymer used in the present invention include homopolymers such as ethylene, propylene, butene, ethylene, propylene,
A copolymer of 5 to 40% (wt%) of olefin such as butene and 60 to 95% of vinyl acetate, or a part of the vinyl acetate in the copolymer with acrylic acid, maleic acid and derivative, vinyl persatite,
Examples include olefin copolymers modified with vinyl propionate.

These may be used alone or in combination of two or more. In particular, in the present invention, polyethylene and ethylene-vinyl acetate copolymers are preferably used. And emulsions of these polymers are usually 15 to 7
It contains 0% resin content. Furthermore, when these emulsions are cast and water removed, a resin film must be formed at a temperature below the decomposition temperature of the blowing agent. Furthermore, if necessary, an emulsion or latex of a rubber-based, vinyl acetate-based, acrylic-based, vinyl chloride-based, alkyd-based, or epoxy-based resin may be added. The thermally decomposable blowing agent used in the present invention is characterized by the melting temperature of the resin, which is the main component of the emulsion, and the heat resistance of the base material.
It usually has a decomposition point of about 120 to 20 mm and has an average particle size of 2 to 8 mm, taking into consideration coating or printing characteristics.
〃 is preferably used.

Examples of such blowing agents include azodicarbonamide, dinitrosobentamethylenetetramine, P,P'
-oxypisbenzenesulfonyl hydrazide, toluenesulfonyl hydrazide, benzenesulfonyl hydrazide, sodium bicarbonate, and the like. These blowing agents are generally used in an amount of 1 to 10 parts, preferably 2 to 5 parts, per 10 parts by weight of the resin in the emulsion. In the present invention, examples of the decomposition accelerator include metal compounds such as zinc white, zinc carbonate, zinc stearate, lead carbonate, lead stearate, and cadmium stearate, urea,
Examples include salicylic acid. These decomposition accelerators are usually used in an amount of 0.1 to 5 for every 10 liters of resin in the emulsion.
part, preferably in the range of 0.5 to 3 parts. Fillers used in the present invention include calcium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, barium hydroxide, antimony oxide,
Average particle size 0.01 to 3, mainly composed of silica sand, clay, etc.
A fine powder of 0 mm, preferably 0.1 to 10 mm is used.

These fillers are usually used in an amount of 70 to 15 base parts per 10 base parts of the resin in the emulsion, preferably 90 to 1.
It is used within the range of Part 3. In the present invention, in order to improve the foaming ratio, smooth the surface of the foam, and increase the hardness, furthermore, improve the water resistance, prevent the composition from running out, and prevent buckling over time, we use an emulsion. A crosslinkable substance may be added as appropriate.

Examples of such crosslinking substances include peroxides such as potassium persulfate and ammonium persulfate, glycidyl methacrylate, N-methylol acrylamide, diallyl phthalate, and N-methylol, taking into consideration the melting temperature and heating temperature of the resin in the emulsion. Compounds having melamine resins, isocyanate groups such as tolylene diisocyanate, carboxyl groups such as trimellitic anhydride, and epoxy groups such as diglycidyl ether are used. Particularly preferred is N-methylolmelamine resin. Since these crosslinkable substances are water-soluble or easily hydrophilic, they can be uniformly dispersed in the emulsion and diffused into the resin, resulting in a large crosslinking effect. However, non-aqueous crosslinking agents capable of fine dispersion such as dicumyl peroxide and 2,5-tert-butyl peroxide can also be used. These crosslinkable substances are used in an amount of usually 0.1 to 1 part, preferably 1 to 5 parts per 10 parts of resin in the emulsion. Although there are no particular limitations on the crosslinking means, not only ordinary heat crosslinking but also radiation crosslinking can be effectively employed. Further, in the present invention, colorants such as pigments and dyes can be appropriately blended into the emulsion as required.

Such coloring agents may be organic pigments, inorganic pigments, or dyes. It is also possible to incorporate metal powder, metal pieces, short fibers, glass beads, glass fibers, paper pieces, stones, etc. into the emulsion as decorative materials. Furthermore, in the present invention, dispersants, wetting agents, antifoaming agents, thickeners, plasticizers, stabilizers, flame retardants, antistatic agents, thickening agents, antioxidants, etc. may be appropriately added to the emulsion. can.

The foamable emulsion used in the present invention is an emulsion of the above-mentioned olefin homopolymer or olefin copolymer, and the above-mentioned foaming agent, decomposition accelerator, filler, furthermore, a foaming substance, a coloring agent, etc. It can be obtained by blending the ingredients in a specific ratio and uniformly emulsifying them using an emulsifying machine or the like.

The foamable emulsion thus obtained is applied or printed on a substrate, and the main component in the emulsion is an olefin homopolymer or an olefin copolymer as described above, and the viscosity of the emulsion is 500 to 250.
Since the ratio P is 0, any base material such as paper, cloth, board, etc.
Coating or printing on films, fibers, etc. can be performed smoothly and efficiently. The foamable emulsion coated or printed on the substrate is heated for about 5 seconds to 5 minutes at a temperature of about 60 to 150° C. above the decomposition temperature of the blowing agent prior to the foaming treatment. As a result, water in the foamable emulsion is removed and the resin composition becomes semi-gelled or gelatinous. After that, increase the temperature to 150
Foaming treatment is performed by raising the temperature to about 180 to 200 oo, preferably about 180 to 200 oo. Such foaming treatment is usually completed in about 2 to 3 minutes. The heating temperature during foaming is 1
If the foam temperature is lower than 50°C, the foaming process will take a long time, which is not only economically disadvantageous, but also the foaming ratio will be low.
The surface of the foam will become uneven, and on the other hand, if it is higher than 25,000, it will foam in a short time, making it difficult to adjust the foaming state, and it will take time to cool down, during which time some shrinkage may occur or the base material may deteriorate. This is not desirable because it can cause After the foaming treatment, the desired foam can be obtained by cooling by natural cooling, forced air, cooling drums, etc. However, for example, in order to enhance the aesthetic value of the foam, it is desirable to add a pattern to the foam. The foam can be embossed using a squeezing roll before cooling, or it can be printed on the foam using a printing roll before or after foaming. By changing it, various aesthetic effects can be achieved. In this way, the book is manufactured through the following steps: preparing a foaming emulsion containing an olefin homopolymer or olefin copolymer as the main component, applying or printing the foaming emulsion onto a substrate, drying, and foaming. The foam of the invention has an extremely high foaming ratio (usually has a foaming ratio of about 2 to 7 times, depending on the application) and is highly economical compared to foams obtained by conventional methods, and can be used as a heat insulating material. It is used as a sound-absorbing material, and because the crimped product has a three-dimensional effect and has extremely high aesthetic value, it does not emit smoke when burned and is easy to perform elutriation treatment, so it can be used as a ceiling material, wall bag material, Suitable for a wide range of applications such as decorative materials and bag materials. In addition, compared to the conventionally widely used polyvinyl chloride foamed leather, the foam obtained by the method of the present invention does not use any plasticizer, but even if it does use it, it is used in a very small amount. Since there is no evaporation of plasticizers, alcohol, etc. released during foaming and processing of Nopaashi, there is no danger or risk of ignition, and there is no pollution caused by contamination. It is an extremely economical and excellent foam as there is no contamination due to migration or leaching. Next, the method of the present invention will be explained with reference to Examples.

Examples 1 to 6 and Comparative Example 1 Foams were manufactured by the following method using materials with the formulations shown in Table 1.

Note that the numbers in Table 1 indicate the number of blended parts. The bottom column of Table 1 shows the viscosity of the foamable emulsion prepared by the method described below. Table 1 In the ingredients listed in Table 1, the powder is mixed with a dispersant,
After dispersing in water together with a wetting agent and an antifoaming agent, this is mixed and dispersed in a resin emulsion together with a crosslinking substance to prepare a foaming emulsion. After applying it so that it is on the 0.12 side, drying it for 3 minutes at 120℃,
The mixture was heated for 1 minute in a heating furnace heated to 100 mL to cause foaming.

The appearance and expansion ratio of the foam obtained are shown in Table 2 below.
Comparative Example 2 Silicone blowing agent 2k9 and calcium carbonate 50k9 were dispersed in ethylene copolymer emulsion 100k9 in the presence of a dispersant and a wetting agent, and then Euromatic (E
After foaming by mixing air under an air pressure of 4k9/cm using a foaming machine manufactured by Yamaichi Matic, it was applied to a thickness of 0.5 ribs using a knife coating machine, and then heated at 200°C. Heat treatment was performed in a furnace for 3 minutes.

The resulting foam had a low expansion ratio as shown in Table 2.
It was sticky, the surface was extremely rough, and the strength was weak. In Table 2, the expansion ratio was calculated using the following formula.

Thickness after foaming Expansion ratio = Thickness before foaming Example 7 Ethylene-vinyl acetate copolymer emulsion 10 Ikari group,
A blend of 3 parts of azodicarbonamide, 1 part of a decomposition accelerator, 3 parts of calcium carbonate, and 2 parts of titanium oxide, with a blue color,
One part each of red and yellow colored pigments was added separately to obtain three types of foamable emulsions.

Next, the foamable emulsion was printed as an ink on wallpaper base paper using a gravure printing machine, and after drying at 110 qo for 5 seconds, it was placed in a 250 qo heating furnace and heated between 2 sands to foam. It was an extremely luxurious item with a raised three-dimensional printed pattern. Example 8 30% of the foaming emulsion of Example 5 was applied to flame-retardant wallpaper lining paper (manufactured by Kojin, trade name WK80NX).
It was coated using a reverse coater and then dried for 49 hours using a hot air dryer at 140°C.

The coating thickness after drying was 0.13 cm. Next, print the pattern for the wall using a gravure printing machine, and then use a 230C0 heating furnace for 1
A bulky high-quality wallpaper was obtained by heating the material for a minute and then passing it through a cooled woven cloth-like squeeze roll.
The obtained wallpaper was subjected to a fire prevention material test according to Ministry of Construction Notification No. 3415, and the results were as shown in Table 3, indicating that it had A-class performance.

Claims (1)

[Claims] 1. A foamable emulsion prepared by dispersing a thermally decomposable blowing agent, a decomposition accelerator, and a filler in an emulsion of an olefin homopolymer or an olefin copolymer is coated or printed on a base material. A method for producing a foam, which comprises heating and drying a foamable emulsion coated or printed on a material to remove moisture, and then foaming the material. 2. The method for producing a foam according to claim 1, wherein a crosslinkable substance is added to the foamable emulsion. 3. The method for producing a foam according to claim 1, wherein the olefin homopolymer is polyethylene. 4. The method for producing a foam according to claim 1, wherein the olefin copolymer is an ethylene-vinyl acetate copolymer. 5 The viscosity of the foamable emulsion is 500 at 25°C.
25,000 cP. A method for producing a foam according to claim 1. 6. The method for producing a foam according to claim 1, wherein the foam is heated at 60 to 150°C for 5 seconds to 5 minutes during heat drying. 7. The method for producing a foam according to claim 1, wherein heating is performed at 150 to 250°C for 20 seconds to 3 minutes during the foaming treatment.