JPS5861124A - Preparation of molded thermoplastic resin article having modified surface - Google Patents

Abstract

PURPOSE:To obtain the titled molded article capable of retaining the improved antifogging property for a long term, by forming a water-insoluble and organic solvent-soluble cationic polyelectrolyte film on the surface of a molded thermoplastic resin article, and adsorbing an anionic surfactant on the resultant film. CONSTITUTION:A water-insoluble and organic solvent-soluble cationic polyelectrolyte, e.g. a copolymer of a monomer having a cationic ionizable group with a vinyl monomer without the ionizable group, is dissolved in an organic solvent, e.g. tetrahydrofuran, and applied to at least one surface of a molded article, preferably a film, sheet or plate, of a thermoplastic resin, e.g. polyethylene, to form a film having about several microns-several tens of microns thickness. An anionic surfactant, e.g. soap of a higher fatty acid such as palmitic acid, is dissolved in a solvent, e.g. water or alcohol, and applied to the resultant film to give the aimed molded article.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a thermoplastic resin molded article whose surface has been modified. More specifically, the present invention relates to a method for producing a thermoplastic resin molded article whose purpose is to impart antifogging properties to the surface of the molded article and maintain this antifogging property for a long period of time.

Conventionally, various thermoplastic resins have been industrially manufactured and used in a wide range of fields. Many of the molded products manufactured from these thermoplastic resins have hydrophobic surfaces, and therefore, depending on the conditions such as temperature and humidity under which the molded products are used, the surfaces may become cloudy, causing various inconveniences. For example, goggles, safety masks, etc. that use synthetic resin lenses may become difficult to see due to freezing, and food packaging films may become cloudy, making it difficult to see the contents. In addition, agricultural films used in greenhouses,
Cloudiness reduces the penetration of sunlight, slowing down plant growth, and causing water droplets to fall on cultivated plants, damaging young buds and causing diseases.

In order to eliminate such inconveniences, it is known that it is sufficient to impart antifogging properties to the surface of the thermo-OJ plastic pattern resin molded product. To impart antifogging properties to the surface of a thermoplastic resin molded product, there is a method of kneading a hydrophilic substance such as a surface-active type into the thermoplastic synthetic resin to make the molded product, or a method of adding antifogging properties to the surface of the molded product after forming the molded product. , a method of applying a hydrophilic substance or a water-bathable polymer has been adopted.

However, in the former method, the hydrophilic substance kneaded into Atsumachi 01J-1 lr oozes out from the surface of the molded product and coordinates to impart antifogging properties to the molded product, but water It has the disadvantage that it is easily washed away by water, and its antifogging properties deteriorate over time. On the other hand, in the latter method, the applied hydrophilic substance or water-soluble polymer easily dissolves in water, so it exhibits excellent antifogging properties immediately after application, but it is easily washed away by water and takes time. As time passes, the protection ability decreases. In order to solve this problem, attempts have been made to reduce the solubility of the hydrophilic substances or water-soluble polymers in water.
However, if this is done, the antifogging property itself will also deteriorate, so it cannot be said to be a satisfactory improvement method.

In addition, a method has been proposed in which a water-soluble polymer applied to the surface of a molded article is crosslinked to reduce its solubility in water. However, this method can only be applied to water-soluble polymers with a specific structure.
After coating the surface of the molded product, it must be removed without causing a crosslinking reaction on the coated surface, making the process complicated and not suitable for IE.

Under such circumstances, the present inventors aimed to provide an industrially advantageous method for imparting antifogging properties to the surface of a thermoplastic resin molded product and maintaining this antifogging property over a long period of time. This was completed after careful consideration.

However, the gist of the present invention is that, in producing a thermoplastic resin molded article with a modified surface, a film of a cationic polymer electrolyte that is insoluble in water and soluble in organic solvents is applied to the surface of the molded article. The present invention relates to a method for producing a thermoplastic resin molded product having a modified surface, which comprises forming a film and adsorbing an anionic surfactant onto the film.

In the following, the present invention will be described in detail. In the present invention, thermoplastic resin refers to polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polycarbonate, polyamides, polyacetal, polyesters, etc. However, the invention is not limited to these examples.

In the present invention, the molded product may be a molded product made of 4 liter resin of Kamiki Netemachi plasticity, and may be a molded product made of 4 liter resin, and there are no restrictions on the shape, dimensions, etc. of the molded product. Among molded products, films,
Sheets, plates, etc. are preferred because they are easy to apply the present invention to.

In the present invention, first, a film of a cationic polymer electrolyte that is insoluble in water and soluble in an organic solvent is formed on at least one surface of the thermoplastic resin 1 and the shaped article. This cationic molecular electrolyte film functions to adsorb an anionic surfactant, which will be described later.

It is necessary to select a cationic polymer electrolyte that is insoluble in water but soluble in organic solvents.

If it is soluble in water, it will be dissolved in water and washed away, making it impossible to maintain the antifogging properties of the molded product, which is undesirable.If it is not soluble in organic solvents, a film will form on the surface of the molded product. This is because it is difficult to do.

In general, what is called a polymer electrolyte is a polymer substance with many ionizable groups, and when dissolved in water, it dissociates into highly charged polymer ions and low molecular ions. Polyelectrolytes with many ionizable groups are soluble in water but insoluble in common organic solvents. When such a polymer electrolyte is applied to the surface of a molded article, it dissolves in the moisture adhering to the surface of the molded article and is washed away.

Even with polymer electrolytes, if the number of ionizable groups is reduced,
There is a large change in the solubility of this substance in solvents, and it shows the property that it is insoluble in water but soluble in certain organic solvents, such as polar solvents and mixtures of polar solvents and water, etc.
Among these solvents, they exhibit the properties of molecular electrolytes.

A cationic polymer electrolyte that is insoluble in water and soluble in organic solvents can be produced by any of the following methods.

(11 A method of copolymerizing a monomer having a cationic ionizing group and a vinyl monomer having no ionizing group.

For example, a method of copolymerizing trimethylaminoethyl methacrylate 9th class ammonium salt and a vinyl monomer.

Examples of copolymerizable vinyl monomers include acrylic acid alkyl esters such as methyl acrylate, ether acrylate, n-propyl acrylate, i-propyl acrylate, i-butyl acrylate, cyclohexyl acrylate, and -monoethylhexyl acrylate. methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, i-butyl methacrylate, cyclohexyl methacrylate, coethylhexyl methacrylate; co-hydroxyethyl acrylate , co-hydroxypropyl acrylate, diethylene glycol monoacrylate, triethylene glycol monoacrylate, tetraethylene glycol monoacrylate, etc. Hydroxyl group-containing acrylic acid alkyl esters; acrylic acid, methacrylic acid, itaconic acid, fumaric acid, acrylonitrile, Examples include methacrylonitrile, styrene, vinyl chloride, etc., but are not limited to these examples.

In order to produce the copolymer, conventionally known methods such as suspension polymerization, emulsion polymerization, solution polymerization, and block type methods can be employed.

(2) A method of grafting a vinyl monomer that does not have an ionizable group onto a cationic polymer electrolyte.

Examples of the cationic polymer electrolyte include polyethyleneimine, polyamine, cationized starch, chitosan, polyvinylbenzyltrimethylammonium chloride, polythiourea, polyvinylpyridine, Mannich-modified polyacrylamide, and polyaminoalkyl methacrylate. These materials are dissolved or dispersed in a mixture of an organic solvent and water, and the vinyl monomers listed in H are grafted onto the mixture.

(3) A method of introducing an amine group or a 9th class ammonium group into a polymer that does not have an ionizing group.

For example, a method in which polyvinyl chloride and an aliphatic amine such as tetraethylenepentamine are reacted in an organic solvent such as tetrahydrofuran.

In the method of the present invention, a cationic polymer electrolyte film produced by the above method that is insoluble in water and soluble in organic solvents is formed on the surface of a molded article. The film formed on the surface of the molded article may cover the entire surface or may be formed on a part of the surface.

To form a film on the surface of a molded article, the above-mentioned water-insoluble but organic solvent-soluble cationic polymer Isolate is dissolved in an organic solvent and applied to the molded article. Examples of organic solvents that can be used in this case include tetrahydrofuran, dioxane, methylene chloride, cyclohexanone, isopropyl alcohol, dimethylformamide, and acetone. These ingredients can be used alone or in combination.

As a method for forming a film on the surface of a molded product, a method can be employed in which coating is applied using a technique that is normally employed when forming this type of film, and an organic solvent is scattered. The coating method can be appropriately selected from roll coating, spray coating, dip coating, knife coating, etc. depending on the shape and size of the molded product. To scatter the organic solvent, a hot air drying method, a drying method using infrared irradiation, or the like can be employed.

The thickness of the film thus formed on the surface of the molded article is preferably in the range of several microns to several tens of microns.

In the present invention, an anionic surfactant is adsorbed onto the film formed on the surface of the molded article by the above method.

The cationic polymer electrolyte previously formed on the surface of the molded product is dissolved in water, and the non-anionic surfactant is such that the moiety that exhibits surface activity in an aqueous solution dissociates into an anion.

Specifically, the following are listed.

Carboxylic acid type φ... Examples include higher fatty acid soaps such as balmitic acid, stearic acid, and oleic acid.

Sodium sulfonate type...11@alkyl sulfonate,
Examples include alkylaryl sulfonate, argylbenzene sulfonate, alkylna-7-talene sulfonate, dialkyl sulfo succinate, and the like.

Sulfate ester type: liquid fatty oil sulfate ester salts, higher alcohol sulfate ester salts, olefin sulfate ester salts, etc.

In order to adsorb the above-mentioned anionic surfactant to the film previously formed on the surface of the molded article, the anionic surfactant is dissolved in a solvent such as water or alcohol, and the cationic surfactant is added to the surface of the molded article. The coating may be applied in the same manner as the molecular electrolyte film is formed.

The ionizing groups of the anionic surfactant and the ionizing groups of the cationic polymer electrolyte film already formed on the surface of the molded product do not need to correspond exactly, and the ionizing groups of the anionic surfactant are on the side. It may be as many as possible.

The present invention has the following effects and has extremely great industrial utility value.

(+i The method of the present invention involves forming a film of a cationic polymer electrolyte that is insoluble in water and soluble in organic solvents on the surface of a thermoplastic resin molded product, and adsorbing an anionic surfactant onto this film. Since this method is adopted, the manufacturing process is not complicated and is industrially advantageous.

(2) The surface of the molded product obtained by the method of the present invention has an improved interface between the cationic polymer electrolyte and the anion, and water droplets adhering to the surface of the molded product are made into a thin film, so it has excellent anticorrosion properties. Become something.

(3) On the surface of the molded article obtained by the method of the present invention, the film formed as a base is made of a water-insoluble cationic polymer electrolyte, so this film will not be washed away by water. In addition, since the anionic surfactant 11 and the cationic polymer electrolyte adsorbed on this film are ionically adsorbed, this material is also difficult to be washed away by water. This treatment maintains the anti-resistance properties of the surface of the molded product for a long period of time.

Hereinafter, the present invention will be explained in detail based on examples.
The present invention is not limited to the following examples unless it exceeds the gist thereof. Incidentally, the cationic polymer electrolyte used in the examples below was synthesized according to the synthesis example shown below.

Synthesis Example/ (Synthesis of vinyl chloride-based cationic polymer electrolyte) Polyvinyl chloride (p-10so) was dissolved in tetrahydrofuran to prepare a solution containing polyvinyl chloride λ.

To this solution 5OO-, tetraethylenepentamine 3/f
was added and refluxed at a temperature of 70°C for 5 hours to react.

Distilled water is added to the reaction solution to precipitate it, purification is carried out, and 5
Vacuum drying was performed at 0° C. for 2 q hours.

When nitrogen analysis was performed on the purified product, the nitrogen content was 0.5.2% by weight.

This product was insoluble in water and also in tetrahydrofuran, which is a solvent for polyvinyl chloride, but was soluble in a mixed solvent prepared by mixing tetrahydrofuran and water in a weight ratio of g to g.

The product was dissolved in a mixed solvent with a weight ratio of tetrahydrofuran to water of g/g to give a 2 weight acid solution.

Synthesis example (synthesis of acrylic cationic polymer electrolyte) Capacity! ;
Into a 00 me reflux and stirrer 3 flask was added 2 kOf isopropyl alcohol (Methyl methacrylate) AOfl Butyl methacrylate 30 g - 1 Ota benzoyl A mixture consisting of peroxide O5f/- was added, and the mixture was reacted for 7 hours at a temperature of goC under a nitrogen stream.

The product was insoluble in water but soluble in acetone, alcohols, ethyl acetate, etc.

The product was made into a solution of isopropyl alcohol.

Synthesis Example 3 (Synthesis of styrene-based cationic polymer electrolyte) General-purpose polystyrene (Mitsubishi Monsanto Chemical Co., Ltd., Dialex HF 7R) U61 was prepared using SO.

- was dissolved in carbon tetrachloride, 10 parts of chlordimethyl ether and 61 parts of zinc chloride as a catalyst were added to this solution, and the mixture was reacted at SOC for S hours to obtain partially chloromethylated polysterene.

Then, this partially chloromethylated polystyrene 5P'k
, /55 me dissolved in dioxane, ? Add 26I triethylamine and SOC! The nitrogen content of the product was 741% by weight and was confirmed to be polystyrene containing about 10 moles of benzyltriethylammonium chloride.

This substance is insoluble in water, alcohols, dimethylformamide, methylene chloride, and Schiff.

It was soluble in hexanone etc.

The product was dissolved in isopropyl alcohol to give a 1-weight solution.

Example/~! Thickness 0. / g of a soft polyvinyl chloride film (manufactured by Mitsubishi Monsanto Kasei ■, vinyl on the right) was coated with the three cationic polymer electrolytes shown in the synthesis example above (Izun was also made into a solution of % by weight). ) was applied by roll coating and dried at a temperature of 12°C.

As shown in Table 1, t% aqueous solutions of various anionic surfactants were applied by spray coating onto the cationic polymer electrolyte film formed on one side of the film. It was dried at a temperature of 0°C.

The film thus prepared was heated to a water temperature of s.

The film was spread on a water tank kept at 0.degree. C. with the coated surface facing down, forming an inclination angle of 5 degrees with respect to the water surface, and the state of condensation of water droplets on the film coated surface was observed with the naked eye. Table 1 shows the observation results of antifogging properties over time.

In Table 1, the indication of anti-fog durability has the following meanings.

A: Showing anti-fog properties equivalent to the one that showed the most aggressive protection immediately after expansion.

B: Showing anti-fogging properties of different grades based on the one that showed the best anti-fogging properties immediately after spreading.

C: Demonstrates the anti-fog properties of six different species, based on those that exhibit excellent anti-fog properties immediately after expansion.

D: Showing anti-fogging properties of q grade based on the one that showed the most excellent anti-fogging properties immediately after expansion.

E: Those exhibiting anti-fogging properties of about 20% or less, based on those exhibiting the most excellent anti-fogging properties immediately after expansion.

Comparative Example/~3 The same flexible polyvinyl chloride film as used in the above practical example, but without forming a film of a cationic polymer electrolyte that is insoluble in water and soluble in organic solvents (Comparative Example/), A film was formed using a 2% by weight acidic aqueous solution of chitosan, which is a cationic polymer electrolyte disoluble in water, in the same manner as described in the above example (Comparative Example 2) and Synthesis Example/ A film was prepared using the prepared material (Comparative Example 3).

Two of the three types of films (Comparative Example/1.2) were further adsorbed with an anionic surfactant in the same manner as described in the above example.

These three types of films were also evaluated for their persistence in prevention using the same method as shown in the above example. The result...3
It is shown in Table 7.

Table 1 (note) *1 Manufactured by Hanada Soap ■, sodium dialkyl sulfosuccinate *2 Manufactured by Tamai Soap ■, sodium alkylnaphthalene sulfonate *3 Manufactured by Tamai Soap ■, sodium lauryl sulfate From Table 1, the following can be found. it is obvious.

(1) The molded article obtained by the method of the present invention exhibits excellent anti-fogging properties, and therefore exhibits excellent antifogging properties.

(2) The antifogging property of the molded product obtained by the method of the present invention is as follows:
It does not deteriorate significantly over time and has excellent anti-fog durability.

(3) On the other hand, those shown in Comparative Examples/C have poor surface wettability and poor anti-fogging durability. The material shown in Comparative Example 3 had poor surface wettability and did not have excellent antifogging properties.

Examples 6 to 10 Thickness 0. / g tm biaxially oriented polystyrene sheet (manufactured by Mitsubishi Monsanto Kasei ■, Sunto Clear), the cationic polymer electrolyte shown in the synthesis example above was applied by roll coating, and dried at a temperature of 0°C. .

On the cationic polymer electrolyte film thus formed on one side of the sheet, 5% aqueous solutions of various anionic surfactants shown in Table 2 were applied by spray coating, and the temperature was 70°C. The sheets prepared as above were dried at left on a water bath kept at 0° C. as shown in Examples 1-S.

The sheet was spread with the coated surface facing the water side and inclined at y2 relative to the water surface, and the state of condensation of water droplets on the sheet coated surface was observed with the naked eye. Table 2 shows the progress of time and the persistence of the antifogging effect.

The indication of anti-fog durability in Table 2 has the same meaning as in Table 1.

Comparative Examples t, S Biaxially oriented polystyrene sheets of the same type as those used in the above examples were not coated with a cationic polymer electrolyte film that was insoluble in water and soluble in organic solvents (Comparative Example 1I) and one in which a film was formed using a 2% by weight acidic aqueous solution gold of chitosan, which is a water-soluble cationic Hatake molecular electrolyte, in the same manner as described in Example 7 (Comparative Example S). 〇An anionic polymer electrolyte was further adsorbed on these two types of sheets prepared in the same manner as described in the above example.

These types of sheets were also evaluated for their anti-fog durability using the same method as shown in the above examples.The results are shown in Table 2.

Although the type of thermoplastic resin in the molded product in Table 2 is different from that shown in Table 1, it is clear from Table 1 that:
O that corresponds to what is clear from this Table 2
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Claims (1)

[Claims] (1) When manufacturing a thermoplastic resin molded product with a modified surface, a film of a cationic polymer electrolyte that is insoluble in water and soluble in organic solvents is formed on the surface of the molded product. A method for producing a thermoplastic resin molded article having a modified surface, characterized by adsorbing an anionic surfactant.