JPH08245301A - Antimicrobial polyurethane molding and its production - Google Patents

Abstract

PURPOSE: To obtain a polyurethane molding, especially a molding comprising a polyurethane foam, being molded by ready operation, not damaging physical properties at all and maintaining excellent antimicrobial properties for a long period of time. CONSTITUTION: A skin layer forming agent comprising 100 pts.wt. of a urethane- based main agent, 5 pts.wt. of a curing agent, 180 pts.wt. of methyl ethyl ketone and 9 pts.wt. of inorganic antimicrobial agent powder having incorporated an antimicrobial metal in the skeleton structure of a zeolite is applied to the inner surface of a mold by a spray method. Then a urethane raw material for an integrally stiffened skin foam is cast into the mold, reacted for 10 minutes, cured and released from the mold to give an arm rest for a chair composed of a polyurethane foam mixed with the antimicrobial agent only on the skin layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antibacterial polyurethane molded article which contains an antibacterial agent only in a skin layer and has excellent appearance and physical properties, and also has sufficient antibacterial property, and a method for producing the same. INDUSTRIAL APPLICABILITY The polyurethane molded article of the present invention is used as an automobile part such as a dashboard, a headrest, an armrest, and a handle, as well as an office equipment, a light electric-related part, and the like.

[0002]

2. Description of the Related Art Polyurethane molded articles having antibacterial properties have been conventionally known, but they are generally added with an antibacterial agent,
Since it is formed of the blended raw materials, the molded product contains the antibacterial agent dispersed and contained almost entirely from the surface to the inside of the molded product. As an antibacterial agent,
Organic antibacterial agents such as nitrogen-sulfur-based and thiabendazole-based agents, and inorganic antibacterial agents in which an antibacterial metal is contained in a porous body are used.

Since the above-mentioned organic antibacterial agent easily exudes to the surface of the molded product due to bleed-out, a large effect can be obtained with a small amount of the compound, but the antibacterial agent is lost from the surface of the molded product with the passage of time, so that the antibacterial property is reduced. However, there is a problem in that it is significantly reduced in a relatively short period of time. On the other hand, since inorganic substances hardly bleed out, stable antibacterial properties are expected over a long period of time, but only the antibacterial agent near the surface of the molded product actually affects the antibacterial action. For,
In order to obtain sufficient antibacterial property, a considerably large amount of antibacterial agent must be added. However, even if a large amount of inorganic antibacterial agent is added, only some of them actually work effectively, and most of the antibacterial agent is wasted, and the molded product becomes heavy, and molding itself is difficult. However, there are many problems such as deterioration of the physical properties of the obtained molded product, and since a large amount of expensive antibacterial agent is added, the production cost is also greatly increased.

[0004]

DISCLOSURE OF THE INVENTION The present invention is to solve the above-mentioned problems, and by adding and blending an inorganic antibacterial agent only in the skin layer of a molded article, an excellent antibacterial effect can be obtained with a small amount of antibacterial agent. It is an object of the present invention to provide a polyurethane molded product, which retains its properties for a long period of time, has good moldability, and does not cause any problems in the physical properties of the molded product, and a method for producing the same.

[0005]

The antibacterial polyurethane molded article of the first invention is a polyurethane molded article comprising a polyurethane substrate and a skin layer formed on the surface thereof,
Only in the above-mentioned skin layer, 0.
It is characterized by containing 5 to 12 parts by weight of an inorganic antibacterial agent.

Further, in the method for producing an antibacterial polyurethane molded article of the fourth invention, a coating agent for forming a skin is applied to the inner surface of a molding die, and then a polyurethane raw material is injected into the molding die to react and cure. After that, in the method of producing a polyurethane molded article by demolding, the coating agent for skin formation is a diluent containing at least a coating main agent and an inorganic antibacterial agent. The above-mentioned inorganic antibacterial agent is 0.5 to 12 parts by weight when the main agent is 100 parts by weight. In addition, a mold release agent is often applied to the inner surface of the mold in advance, and in this case, the coating agent for forming a skin is applied to the inner surface of the mold via a release agent film. Become.

The polyurethane forming the "polyurethane substrate" is not particularly limited, and an elastomer or foam is generally used. In the present invention, however, as in the second invention,
Particularly excellent effects are exhibited when the substrate is a foam. This foam substrate can be manufactured, for example, by reaction injection molding (RI
Flexible foam molded by a casting method including M method), etc.,
The molded article of the present invention, which is formed of a semi-rigid foam such as integral skin foam and a rigid foam, has a skin layer formed separately from the substrate, and is particularly large when the substrate is a semi-rigid foam or a flexible foam. The effect is obtained. As a raw material for producing these elastomers or foams, those usually used for their production can be used without particular limitation.

For example, in the RIM method, polyether polyol and MDI-based isocyanate are frequently used, and in integral skin foam, a long-chain polyol and polyisocyanate are combined with a foaming agent such as chlorofluorocarbon which easily forms a skin layer. used. Further, in the polyurethane flexible mold foam, as the polyol component,
Polyether having a molecular weight of about 3,000 to 7,000 containing a primary hydroxyl group, polymer polyol blended product, etc. can be used, to which an amine-based catalyst or a mixed amine-tin catalyst, a low-activity silicone-based foam stabilizer and water are added. As the isocyanate component, various ones such as TDI, TDI / MDI, and MDI can be used.

If the content of the "inorganic antibacterial agent" in the "skin layer" is less than 0.5 parts by weight, a molded article having sufficient antibacterial properties cannot be obtained, and if the content exceeds 12 parts by weight. Not only does not show any further improvement in antibacterial properties,
The hardness of the skin layer becomes too high due to the incorporation of a large amount of inorganic substances, and the skin layer becomes hard and brittle, which is not preferable.
The content of this antibacterial agent is preferably 1 to 4 parts by weight as in the third aspect of the invention. Within this range, sufficient antibacterial properties are obtained and the physical properties are not impaired at all.

The "skin-forming coating agent" for forming the skin layer in the fourth invention is a material for forming the surface layer of the molded article, and therefore has the required mechanical strength and feel. However, since the base material is polyurethane, it is preferable that the above-mentioned "coating agent" in the coating agent for skin formation is also a urethane-based material. Examples of such a coating agent for forming a skin include a urethane-based alkyd-based, urethane lacquer-based, etc., room-temperature-drying type urethane-based coating material. If these urethane-based materials are used, the substrate injected into the mold It is preferable that the raw material reacts and cures to be bonded to the skin layer with sufficient strength.

In the urethane-based paint as described above, a main component and a curing agent are generally dissolved or dispersed in a "diluent", and in the present invention, an "inorganic antibacterial agent" is further added thereto. ing. As the diluent, an organic solvent is generally used, and a solvent having no active hydrogen that reacts with an isocyanate group such as alcohols, for example, an ester or a ketone is used. Further, as the inorganic antibacterial agent, synthetic zeolite, natural zeolite, glass, silica-alumina magnesia, zirconium phosphate, silica gel, phosphate, phosphate double salt, calcium phosphate, a porous body made of an inorganic substance such as calcium silicate. An inorganic antibacterial agent containing an antibacterial metal such as silver, copper or zinc can be used.

If the amount of the above-mentioned inorganic antibacterial agent is less than 0.5 parts by weight with respect to the main coating agent, sufficient antibacterial properties cannot be obtained, and 1
If it exceeds 2 parts by weight, not only further improvement of antibacterial property is not observed, but also the hardness of the skin layer becomes too high, the mechanical strength etc. is lowered, and further the antibacterial agent precipitates in the compounding container. Sometimes it is not preferable. Further, the diluent such as an organic solvent constituting the coating agent for forming a skin is 100% of the coating main agent.
100 to 250 parts by weight, especially 150 to 2 parts by weight
The range of 00 parts by weight is preferable, and when the diluent is less than 100 parts by weight, the viscosity of the coating agent for forming a skin becomes too high, and it becomes difficult to form a coating film having a uniform thickness by, for example, a spray method. On the other hand, when the amount of the diluent exceeds 250 parts by weight, it may be necessary to remove the diluent after coating, and the thickness of the skin layer formed by volatilizing the diluent becomes thin. As a result, the content of the antibacterial agent in the epidermis layer becomes insufficient, and the antibacterial property decreases, which is not preferable.

[0013]

The present invention will be described below in detail with reference to examples. Examples 1 and 2 and Comparative Example 1 A case of manufacturing an armrest of a chair will be described below as an example. The following components were mixed in the proportions shown in Table 1 to prepare a coating agent for forming a skin, and sprayed onto the inner surface of a mold having a release treatment of about 40 to 50 ° C by a spray method. After the coating, the urethane raw material for integral skin foam was poured into the mold, reacted and cured for 10 minutes, demolded, and left for 1 week at room temperature to obtain the appearance, abrasion resistance and antibacterial property of the product. evaluated.

Each component constituting the coating agent for skin formation: coating main agent; manufactured by MIKUNI PAINT Co., Ltd., trade name "UL"
-Grage 7-4-7620 "Curing agent; manufactured by Mikuni Paint Co., Ltd., trade name" DO
8-251 "antibacterial agent; manufactured by Shinagawa Fuel Co., Ltd., trade name" Zeomic "
AW-10N ", an inorganic antibacterial agent containing zeolite, and antibacterial metals such as silver, copper, zinc; organic solvent; methyl ethyl ketone

[0015]

[Table 1]

[0016] In Table 1, each numerical value is the coating film main agent 10
Represents parts by weight when the amount is 0 parts by weight. The numerical value in the parentheses in the column of antibacterial agent represents the weight% of the antibacterial agent when the total amount of the coating agent for forming a skin is 100% by weight.

Each of the skin-forming coating agents shown in Table 1 had no problem in the operation of spray-coating by the spray method, and the appearance of the product after the mold release was visually observed. Examples 1 and 2 and Comparative Example In all cases of Example 1, it was good. Also, the wear resistance was excellent in each case, and there was no problem.

Next, the antibacterial property of the molded article obtained as described above was evaluated by the following method. A test piece with a size of 45 × 55 mm was cut out from the same corresponding part of each molded product, treated with hot water at 80 ° C. for 1 hour, and 1 ml of the bacterial solution was dropped on the surface of the test piece, and at 37 ° C. for 24 hours. Cultured. Then, 10 ml of sterilized phosphate buffer
The bacteria were washed out by. The washed-out buffer solution was used as a sample solution, and the number of viable bacteria in the sample solution was measured by a pour plate method using a medium for measuring the number of bacteria. Further, as a control, a test using only the bacterial solution was also performed. Staphylococcus aureus and Escherichia coli were used as bacteria. Table 2 shows the results. The unit of the numerical values in Table 2 is "piece".

[0019]

[Table 2]

According to the results shown in Table 2, no Escherichia coli was detected in Example 1 containing an antibacterial agent close to the upper limit amount, and Staphylococcus aureus was 1/100 of that in Comparative Example 1. It can be seen that the molded product has excellent antibacterial properties. Also,
In Example 2 in which the amount of the antibacterial agent was reduced to 2/9 of that in Example 1, no remarkable effect was observed with Staphylococcus aureus, but it was still superior to Comparative Example 1, and the number of Escherichia coli was higher than that of Comparative Example 1. It is about 1/1000, and it can be seen that the effect of compounding the antibacterial agent is sufficiently exhibited.

As described above, in the antibacterial polyurethane molded article of the present invention, the molding operation and the finish, physical properties and the like of the molded article obtained are such that the molded article using a conventional organic antibacterial agent or the entire inorganic molded antibacterial agent is used. It can be seen that excellent antibacterial properties are obtained with no difference in the amount of the antibacterial agent, which is no different from the molded product containing the agent.

[0022]

According to the antibacterial polyurethane molded products of the first to third inventions, since the inorganic antibacterial agent is used, the antibacterial effect is rapidly lost with time as in the case of the organic antibacterial agent. In addition, since the antibacterial agent is mixed only in the epidermis layer, a sufficient amount of antibacterial effect can be obtained with a small amount of the antibacterial agent, and since the antibacterial agent is in a small amount, the antibacterial agent is mixed and applied to the mold, etc. There is no problem in molding operation, and the physical properties of the obtained molded product do not deteriorate. Furthermore, according to the method for producing an antibacterial polyurethane molded article of the fourth invention, an antibacterial polyurethane molded article can be produced by the same operation and process as molding of a normal polyurethane molded article, and
By setting the concentration of the inorganic antibacterial agent within the range specified in the fifth invention, it is possible to more easily produce a polyurethane molded article having high antibacterial properties.

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Claims (5)

[Claims] 1. A polyurethane molded article comprising a polyurethane substrate and a skin layer formed on the surface of the polyurethane substrate, wherein the surface layer alone has a content of 0.
An antibacterial polyurethane molded article comprising 5 to 12 parts by weight of an inorganic antibacterial agent. 2. The antibacterial polyurethane molded article according to claim 1, wherein the polyurethane substrate is polyurethane foam, and the skin layer is made of a urethane-based paint. 3. The antibacterial polyurethane molded article according to claim 1, wherein the content of the inorganic antibacterial agent is 1 to 4 parts by weight. 4. A coating agent for forming a skin is applied to the inner surface of a molding die, and then a polyurethane raw material is injected into the molding die,
In the method of producing a polyurethane molded article by reacting and curing, and then releasing from the mold, the skin forming coating agent is a diluent containing at least a coating main agent and an inorganic antibacterial agent, The method for producing an antibacterial polyurethane molded article, wherein the inorganic antibacterial agent is 0.5 to 12 parts by weight when the coating film main agent is 100 parts by weight. 5. The method for producing an antibacterial polyurethane molded article according to claim 4, wherein the content of the inorganic antibacterial agent is 1 to 4 parts by weight.