JPS63248643A - Manufacture of material for packaging with foam - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention mainly relates to a method for manufacturing a packaging material having a cushioning function and is provided with a foam. This invention relates to a method of foam-molding a foam directly onto the surface of a packaging material without using any foam.

This point will be further explained by giving a specific example.

For example, when automobile assembly parts are casually placed inside a paper bag and transported, there is no cushioning material on the inside of the bag, so there is a certain chance that the parts will rub against the inside of the paper bag and cause scratches. It was considered unavoidable.

Paper packaging bags for edible rice are currently on the market, but they are made of multiple layers of paper to provide cushioning.

Furthermore, in bags used for mailing books, fiber cotton is inserted into the two-layer bag to provide cushioning properties.

In place of these products, this invention can manufacture bags with high cushioning properties by molding a foam layer of several millimeters on the inside or outside of paper bags, and can also be applied to the inner and outer surfaces of fragments of so-called partitions. It is intended to mold foam onto the inside and outside surfaces of cardboard boxes, the surfaces of glass bottles, etc.

(Conventional technology) The inventor is not aware of any known examples of this type of molding method.

In a known method, a mold is made in advance, and concave packaging materials are manufactured using this mold to match the external shape of the packaged item, but this method requires the production of a mold one by one. Not only does it take a long time to manufacture, but the cost of molds is not cheap, so packaging materials are relatively expensive.

Separately produced urethane sheets or foam sheets are also widely bonded to the inner surface of the cardboard box using an adhesive.Although this practice has been carried out, it is time-consuming and the sheets tend to peel off easily. .

(Problems to be Solved by the Invention) The present invention is to easily mold a foam directly onto the surface of a packaging material without requiring any special production equipment.

Another object of the present invention is to obtain a novel packaging material that is rich in taste by molding the foam into an arbitrary shape.

Other objectives will be understood from the description below.

[Structure of the invention]

(Means for Solving the Problems) The basic structure of this invention consists of corrugated paper, wooden boards, cloth,
A foamed thermoplastic synthetic resin emulsion diluted with water is applied to the surface of an appropriate packaging material such as glass, depending on the application, and then the applied emulsion is dried to remove or reduce the water content in the emulsion. This is a method of heating the foamed thermoplastic synthetic resin with a heat source at a relatively low temperature to foam the foamed thermoplastic synthetic resin to form a foam on the surface of the packaging material.

(Embodiments of the Invention) Various methods for producing foamed products have been known.

For example, ■ Method using mechanical stirring ■ Method using gas by-produced during chemical reaction ■ Method of mixing or impregnating with a low boiling point volatile solvent and vaporizing it ■ Method of pressurizing liquefied gas ■ Micro balloon Method for incorporating (hollow air spheres) Methods include adding a soluble substance and eluting it.

However, packaging materials are inevitably subject to restrictions due to their nature.

The inventor has determined through experiments that it is most advisable to use a blowing agent.

Various foaming agents can be considered, but one that satisfies requirements such as being easily available, being inexpensive, being suitable as a packaging material, and requiring only a small amount of production equipment. The inventor experimentally selected the following. □ Specific examples of blowing agents will be described later, but the term blowing agents used herein are those that are mixed with rubber or plastics and decomposed by heat treatment, producing nitrogen gas, carbon gas, carbon oxide gas, carbon oxide gas, etc. in the base material. A general term for agents (gas generating agents) that generate ammonia gas, sometimes hydrogen gas, etc. to form cell structures.

Blowing agents are broadly classified into organic blowing agents and inorganic blowing agents, but inorganic blowing agents (e.g. sodium bicarbonate, ammonium carbonate, sodium boron hydride, silicon oxyhydride) generally have a slow gas generation rate. Therefore, it was difficult to adjust the gas generation, and there were many problems with its adoption, but if this adjustment can be solved in the future, it should be considered for use.

Organic blowing agents are suitable for carrying out the invention because they have an appropriate rate of gas generation upon thermal decomposition and the decomposition temperature can be easily adjusted by adding an auxiliary agent.

Since the generated gas is mostly nitrogen gas, it is suitable for this invention because uniform and fine single cells can be obtained.

Theoretically possible blowing agents for this invention include:

1. Chemical name: Azodicarbosoamide decomposition temperature: 200-210°C Amount of gas generated: 200-230 m1/g (at 0°C and 1 atm) In liquid paraffin 2. Chemical name: Azobisisobutyronitrile decomposition temperature: 9
8 to 102°C Amount of gas generated: 124 m1/g (at 0°C, 1 atm) 3 in liquid paraffin, chemical name: para-toluenesulfonylhydrazide decomposition temperature, 103 to 111°C Amount of gas generated, 120 m1/g (at 0°C, 1 atm) ) In addition to liquid paraffin, effective blowing agents for this invention include:

Main component: Ethylene-vinyl acetate copolymer blowing agent.Azobisisobutyronitrile blowing agent is not put into the main component solution as a single item, but it is better to put it in microcapsule form. For example, it is preferable to encapsulate it with vinylidene chloride (PVC type).

Simply microcapsule butane gas For example, the temperature at which the capsule is Sufficient foaming occurs when decomposed and melted at 100℃ Acts as an agent.

Dispersant: Added to ensure that the main component and foaming agent are evenly dispersed in water and that foaming occurs smoothly. Mainly suitable are methylcellulose, carboxymethylcellulose, polyvinyl africol, and the like.

The foamed thermoplastic synthetic resin emulsion used in this invention is basically obtained in a state in which the above three components are dissolved in water.

Note that the main component can be broadly understood to be an olefin resin.

Acrylic resin can also be used as the main component.

The following is an experimental example of this invention.

The solid content was 50 to 55% and the viscosity was 10.0 OQ cps to 20,000 ps, but these points can be changed freely.

In addition, the viscosity is 2.500 cps to ±500 ps. 5. 000 c ps ~ ±1,000 ps The later one was adopted.

Although the foaming ratio is about 10 times, it has been found that it can be changed from several times to several tens of times depending on the application.

Next, the packaging and dressing materials will be explained.

corrugated paper, wooden boards, fabrics, glass, plastics,
In principle, the type of material, such as metal, does not matter.

Particularly effective ones were those with rough surfaces, but the invention is not necessarily limited and can also be applied to glass bottles with smooth surfaces.

Experimentally, it was also possible to mold foam onto the surface of glass, for example.

Therefore, it was possible to freely mold foam onto the surfaces of glass bottles, the inside and outside of cardboard boxes, the surfaces of fabrics, etc.

Therefore, the foamed thermoplastic synthetic resin emulsion described above is applied thinly to the surface of the packaging material using a brush, roller, or the like.

By adding a coloring agent to this emulsion, a colored foam can be molded.

When a coloring agent is added, unlike an uncolored foam, the molded foam has the advantage that it can be of any color rather than just white.

In principle, the type of colorant may be a commercially available product, but is not particularly limited as long as it does not chemically change the blowing agent.

When applied, it may be applied to the entire surface of the packaging material, but
As long as it does not affect the packaged item, it may be applied in a linear manner at regular intervals without being applied over the entire surface, or the packaged item may be decorated in a so-called illustration style, or a trademark may be displayed. A foamed thermoplastic synthetic resin emulsion may also be applied.

It is clear that packaging materials provided with foam in this way can be offered commercially as a novelty in combination with color indications.

In this case, the emulsion described above may be used as it is, but since a relatively hard foam is formed, it goes without saying that it may be used after being dissolved in water if necessary. It is used by dissolving it in water depending on the situation.

If the foam is made thinner, a flexible foam can be obtained; if the foam is made thicker, a relatively hard foam can be obtained; It is easy to understand that it can be changed freely depending on the settings.

Although water is inexpensive and functional, it is not limited to water; for example, an alcohol solution may be used.

That is, there is no restriction as long as it is an aqueous solution having an OH group.

Even if the emulsion is then foamed immediately after application, it generally contains a relatively large amount of water, which slows down the gas generation rate, so the emulsion is dried to remove or reduce the water content. .

This drying means may be left to stand after application, or may be actively dried at low temperature.

The above-mentioned emulsion is sufficiently foamed at a relatively low temperature, for example, at most about 100° C. as in the above-mentioned example.

However, this 100°C does not mean that it is the only low temperature.

Therefore, as long as the packaging material does not deteriorate due to heating, there is no problem even if the temperature is slightly higher or lower.

If the temperature is too low, the disadvantage is that the foaming time becomes longer, so if this point is taken into consideration, a low temperature may be used.

The water content of the applied emulsion is removed or reduced after the drying process, so that the emulsion changes from an emulsion state to a solid state in which only the foamed thermoplastic synthetic resin remains in principle.

Therefore, the foamed thermoplastic synthetic resin is subjected to relatively low heating.

This heating time is about 1 minute at most.

When the foamed thermoplastic synthetic resin is heated, it expands by about 4 to 20 times in volume due to a foaming reaction, and a three-dimensional foam is formed on the surface of the packaging material.

In this specification, the three-dimensional foam is defined as several mm to 5 mm.
An example of a diameter of about 0 mm is given.

In this explanation, as an example, molding foam on the surface of a cardboard box was given, but it is also planned to mold foam on the inner and outer surfaces of partitions.

It was also possible to form foams on packaging materials such as the inner and outer surfaces of wooden boxes, fabrics, glass, and metal surfaces.

Therefore, although there are many packaging materials that generally require cushioning properties, their uses are not limited in principle.

(Effects of the Invention) Since the present invention has the above configuration, it has the following advantages.

(1) Unlike conventional foam molding methods, molding can be performed directly onto the surface of the packaging material itself, so no molds or production equipment are required.

Therefore, it is extremely easy to carry out, and a wide variety of products in small quantities can be produced flexibly.

(2) Since it is based on the process of applying the foamed thermoplastic synthetic resin to the packaging material and heating it, it can be easily carried out and the production cost can be reduced compared to conventional methods.

(3) The foamed thermoplastic synthetic resin emulsion can be applied by drawing letters, figures, symbols, etc. as appropriate;
Since the foam that performs the cushioning function can be molded into any three-dimensional shape, it is possible to obtain packaging materials that are novel and rich in taste that have not been seen before.

(4) Even when foamed thermoplastic synthetic resin is foam-molded onto a smooth glass surface, for example, it has a relatively high adhesive function and will not peel off easily.

Claims (1)

[Claims] If necessary, a foamed thermoplastic synthetic resin emulsion dissolved in water is applied to the surface of an appropriate packaging material such as paper, wood, cloth, glass, or metal, and then the above-mentioned emulsion is applied. The moisture in the emulsion is removed or reduced by drying, and then the foamed thermoplastic synthetic resin is heated with a heat source at a relatively low temperature, and the foamed thermoplastic synthetic resin is foamed to form a foam on the surface of the packaging material. A method for producing a packaging material comprising a molded foam.