JPS60240770A - Surface protecting agent - Google Patents

Abstract

PURPOSE:To provide a surface protecting agent suitable for use in coating furnishings, hardware, earthen-ware, glassware, etc., consisting of a specified partially saponified polyvinyl acetate resin. CONSTITUTION:A partially saponified polyvinyl acetate resin having an average degree of polymn. of 50-1,500 and a degree of saponification of 10-50mol% is used as a surface protecting agent. A soln. (10-60wt%) of said agent is applied to the surface of a material and dried, or said agent is molten by heating, applied to said surface and allowed to stand to cool, thus forming a protective film. The resulting film has excellent mechanical strength and an excellent effect of protecting the surface of the material from being mechanically marred or stained. When it is no longer necessary to protect the surface, the film can be removed easily and completely by bringing it into contact with a small quantity of water and slightly wiping off it.

Description

[Detailed description of the invention] The present invention relates to a novel surface protection agent.

Traditionally, furniture, metal products, ceramics, glass, etc.

During handling or transportation, the surface of the product may become contaminated or be damaged by slight friction or impact, which can significantly reduce its commercial value, and a solution to this problem has been required. As a countermeasure against this, conventional methods have been to form a film by applying an aqueous polyvinyl alcohol solution or polyvinyl acetate emulsion to the surface to prevent contamination and damage to the surface, and then to remove the protective film by dissolving it with water after the purpose has been achieved. It is being said. However, in the case of polyvinyl alcohol, it dissolves only slightly in a small amount of water, but it is much more sticky than when it is dry and cannot be easily wiped off, and it takes time to completely remove it. Rinsing with copious amounts of water was necessary. Also, in the case of polyvinyl acetate emulsion, a small amount of water causes it to swell, turn white, and only partially dissolve, making it highly sticky.
It was difficult to remove. Therefore, as with polyvinyl alcohol, a large amount of water was required to completely remove it. In addition to this method, there is a method of attaching a film such as polyethylene to the object using an adhesive, but the adhesive surface is limited to a flat surface, and the adhesive often remains partially on the surface after it is removed, contaminating the surface. That leaves a problem.

However, the present inventors solved the difficulties of these protective agents, and created a protective agent that can be easily and completely peeled off as a whole, and has an adhesive strength that will not peel off naturally during the intended protection period. As a result of extensive research to develop a surface protective agent, the average degree of polymerization ranged from 50 to 1500. The degree of saponification is 10 to 50 mol%, preferably the average degree of polymerization is 100 to 1000. The film formed by applying a partially saponified polyvinyl acetate resin with a saponification degree of 10 to 40 mol% on the surface to be protected has excellent mechanical strength and is resistant to mechanical damage and contamination of the protected object. It has an excellent protective effect, and when it is time to achieve its purpose and remove it, it swells with just a small amount of water and can be completely removed from the surface of the object to be protected by just wiping it lightly. We discovered the fact that the swollen film does not peel off naturally, and once it dries, it regains its original excellent protective effect, making it possible to use it outdoors.9 The present invention has now been completed.

That is, the present invention is a surface protective agent comprising a partially saponified polyvinyl acetate resin having an average degree of polymerization of 50 to 1500 degrees and a degree of saponification of 10 to 50 mol%.

In the present invention, when the average degree of polymerization of the polyvinyl acetate resin moiety is less than 50, the mechanical strength of the film decreases and it becomes difficult to exhibit a sufficient protective effect.

On the other hand, if the average degree of polymerization exceeds 1,500, the adhesion to the object to be protected upon swelling with water will be greater than necessary, making it difficult to easily peel off the film. In addition, if the degree of saponification is less than 10 mol%, it will be difficult to swell with a small amount of water, and the film will not be easily removed.On the other hand, if the degree of saponification exceeds 50 mol%, a small amount of It is difficult to remove with water and requires rinsing with a large amount of water to completely remove it.

By applying the protective agent of the present invention to the tile surface,
Even if excess concrete that protrudes from the tile seals during tile installation adheres to the surface, it will not be melted by the moisture in the concrete, completely preventing concrete from adhering to the tile surface. Once the concrete has hardened, it can be completely removed by simply moistening it with a little water and wiping it gently. Also, by applying it to the surface of metal plates and metal products, it has the effect of preventing the formation of rust, and even if it is left outside and exposed to the rain, it will only swell and dry repeatedly. It does not peel off and exhibits excellent protection including rust prevention over a long period of time. Furthermore, by applying it to the surface of glass plates, glass products, or ceramics, it provides excellent protection against surface contamination and mechanical damage, and also prevents fragments from scattering in the event that the glass or ceramics is broken. It also shows excellent effects. In addition, it is extremely useful for temporarily protecting the surface of molded products in a wide range of fields such as surface treatment of concrete or cement mortar, plastic products, and furniture.

As a method for forming a film on the surface of an object to be protected using the surface protecting agent of the present invention, for example, 1. using the surface protecting agent.

Method 2 The surface protective agent is dissolved in an organic solvent or in a mixed solution of an organic solvent and water, preferably at a concentration of 10 to 60% by weight, and applied to the surface of the object to be protected and dried to form a film. A method can be adopted in which a film is formed by coating the surface of the object to be protected in a heated and molten state and cooling.

Application methods when using a solvent include 2, for example, roller H, spacing, spraying, dipping, etc.
The present invention is not necessarily limited to these, and if necessary, a support such as paper or nonwoven fabric may be laminated on the solution-coated surface. In addition, examples of organic solvents that can be preferably used here include methanol, ethanol, and propatool.

Isopropanol, n-butanol, 5ee-butanol, isobutanol, acetone, methyl ethyl ketone,
Examples include, but are not limited to, methanol/methyl acetate. A true melt coater or the like may be used for application by heating and melting, but is not particularly limited thereto.

Furthermore, it is also possible to bond a support in the same way as when applying a solution. This application does not require any drying time, so it is particularly effective when processing the surfaces of plate-shaped molded products in large quantities, such as glass plates and aluminum plates.

2. Plasticizers such as glycerin, polyethylene glycol, and higher alcohols, surfactants 1. Rust preventive agents, and other inorganic pigments such as clay can be added to the surface protective agent of the present invention, if necessary.

EXAMPLES The present invention will be explained in more detail with reference to Examples below.

Note that "parts" in the two examples mean "parts by weight."

Example 1 Degree of polymerization: 380. 30 parts of a partially saponified polyvinyl acetate resin having a degree of saponification of 35 mol%, 21 parts of water, and 49 parts of isopropanol were mixed at room temperature, stirred, and dissolved. Next, the obtained solution was applied to an aluminum plate using a 0.2 mm applicator and dried at room temperature to form a transparent dry coating film with a thickness of 50 μm. This did not peel off even after being left at room temperature for three months. Also.

When this coating film was sprayed with cold water, the coating swelled without dissolving, and could be completely removed by wiping it gently.

Comparative Example 1 Degree of polymerization: 380. The same procedure as in Example 1 was carried out except that 30 parts of a partially saponified polyvinyl acetate resin having a degree of saponification of 68 mol%, 42 parts of water, and 28 parts of isopropanol were used.

When the resulting coating film was sprayed with cold water, it dissolved and was difficult to completely remove by just wiping it lightly.

Comparative Example 2 Degree of polymerization: 380. 30 parts of partially saponified polyvinyl acetate resin with saponification degree of 5 mol%, 7 parts of water, and 63 parts of isopropanol
The same procedure as in Example 1 was carried out except that 100% of the sample was used. Even when the resulting coating film was sprayed with cold water, it swelled very slowly and was difficult to wipe off easily.

Examples 2 to 8 Solutions were obtained in the same manner as in Example 1 except that various partially saponified polyvinyl acetate resins, lower aliphatic alcohols, and water shown in Table 1 were used in the amounts shown in Table 1. This solution was applied to a glass plate, dried at room temperature, and left at room temperature for one month, after which the condition and releasability of the coating film were examined. In addition, the coating on the glass plate is 0.
It was performed using a 2 mm applicator and dried in 0.5 to 1 hour.

The peel test was measured by the removal rate when water at 20°C was sprayed and gently wiped off. The results obtained are shown in Table 1.

Example 9 When the solution of Example 1 was applied to a tile with a brush and dried, a film with a thickness of 60 μm was formed. When this tile was pasted with concrete, a tile panel was created, and the concrete that protruded from between the tiles adhered to the tile surface, but although the paint film swelled due to the moisture contained in the concrete, it did not dissolve or naturally peel off. After the concrete had dried and solidified, it was easily removed along with the paint film by simply spraying it with cold water and wiping it off.However, there was no trace of concrete adhering to the tile surface.

Example 1.0 Degree of polymerization 260. A partially saponified polyvinyl acetate resin having a degree of saponification of 37.5 mol % was heated and melted at 150°C, coated on an aluminum plate with true melt coke, and cooled to form a coating film with a thickness of 30 μm. This film did not naturally peel off even after being left at room temperature for three months and had sufficient protective action. Furthermore, when this coating film was sprayed with cold water, it swelled without dissolving, and could be completely removed by wiping it gently.

Claims (1)

[Claims] (11 Average degree of polymerization is 50 to 1500. Degree of saponification is 10
A surface protection agent consisting of 50 mol% of a partially saponified polyvinyl acetate resin.