JPH05278041A - Polyurethane remover - Google Patents

Abstract

PURPOSE:To prepare a polyurethane remover having an easy handleability and a superior capability in removing a polyurethane adhering to a molded piece or the like by incorporating a dimethyl sulfoxide with a sodium hydroxide and/or a potassium hydroxide. CONSTITUTION:A polyurethane remover is applied for removing a polyurethane adhering to a molded piece made of a glass or a metal after, esp., a polyurethane lens casted and polymerized is released. In this invention, a polyurethane remover is prepared by incorporating a dimethyl sulfoxide with a sodium hydroxide and/or a potassium hydroxide. As a preferable example, the use ratio of a sodium hydroxide and/or a potassium hydroxide is determined to be 0.01-100 pts.wt. per 1 pts.wt. of a dimethyl sulfoxide. Furthermore, water as a diluent, a carboxylic acid having a cleaning effect, and the like are incorporated. In this manner, the obtained polyurethane remover has an easy handleability and a superior removing capability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyurethane remover, and in particular, it removes the polyurethane adhering to a mold made of glass or metal after cast-polymerizing a polyurethane lens to release it. To a polyurethane remover suitable for

[0002]

It is well known to manufacture polyurethane lenses by cast polymerization. It is also well known that when a polyurethane lens is released from a mold made of glass, metal or the like, the polyurethane lens residue adheres to the mold and the deposit cannot be easily removed. . As a method for solving this problem, for example, JP-A-1-14498 discloses a polyurethane removing agent containing dimethyl sulfoxide and trichlorethylene.
Further, JP-A-58-20422 discloses a polyurethane remover obtained by adding an amine salt of fatty acid to dimethyl sulfoxide, and JP-A-62-243697 discloses a remover comprising dimethyl sulfoxide and an alkali metal organic compound. It is disclosed.

[0003]

However, the polyurethane removing agent disclosed in the above-mentioned JP-A No. 1-14498 has a function of swelling the attached polyurethane, but it is described in this publication. It does not have the action of dissolving polyurethane as it does. Therefore, the ability to remove polyurethane becomes insufficient, and it takes a long time to completely remove the polyurethane attached to the mold.

Further, the removing agent disclosed in Japanese Patent Application Laid-Open No. 58-20422 has an insufficient ability of removing polyurethane.
As described in this publication, there is a problem that a long removal time of 24 hours is required.

Further, the removing agent disclosed in JP-A-62-243697 uses an alkali metallized organic compound such as sodium hydride and calcium hydride. These substances have the property of decomposing in moist air or reacting violently with water to generate hydrogen. Therefore, this remover has a drawback that it is difficult to handle. The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide a polyurethane removing agent which is easy to handle and has excellent polyurethane removing ability.

[0006]

The above objects have been achieved by a polyurethane scavenger which is characterized in that it contains dimethylsulfoxide and sodium hydroxide and / or potassium hydroxide.

The present invention will be described in detail below. In the present invention, dimethyl sulfoxide (hereinafter, simply referred to as "DMSO") and sodium hydroxide and / or potassium hydroxide are essential components. (Hereinafter, a solution consisting of these essential components may be simply referred to as an "essential component solution".) The reason is that the combination of these essential components makes handling relatively easy and has a polyurethane removal capacity better than that of conventional removers. This is because they have found that they are also superior. Use one of sodium hydroxide and potassium hydroxide,
Further, they can be mixed and used. The usage rate is not limited.

The proportion of DMSO and sodium hydroxide and / or potassium hydroxide used is in the range of 0.01 to 100 parts by weight of sodium hydroxide and / or potassium hydroxide to 1 part by weight of DMSO. preferable. The reason is that if it is less than 0.01 parts by weight or more than 100 parts by weight, a synergistic effect cannot be obtained, and sufficient polyurethane removing ability is not obtained. In addition, a particularly preferable range is 0.03 parts by weight of sodium hydroxide and / or potassium hydroxide to 1 part by weight of DMSO to 0.4 parts by weight.
A range of parts by weight is preferred.

The polyurethane removing agent of the present invention may contain optional components in the above-mentioned essential component solution, if necessary. As an example thereof, water used as a diluent, or a substance known to have a cleaning effect from the past, for example, carboxylic acid, sulfate, anionic surfactant such as phosphoric acid compound, alkylene oxide compound,
Nonionic surfactants such as amine oxides and sulfoxides, cationic surfactants such as amine compounds, inorganic acids such as nitrates, silicates, carbonates and borates, hydrochlorides such as sodium chloride and potassium chloride, Inorganic compound containing halogen, organic compound containing oxygen such as alcohol and glycerin, organic compound containing nitrogen such as amine compound and amide compound, organic compound containing phosphorus, chelate compound, Si
Including organic compounds.

The method of using the polyurethane removing agent of the present invention includes, for example, a mold to which polyurethane is attached,
Examples include a method of immersing a jig or the like in a remover and a method of applying only to a place where polyurethane is attached, but the former method is preferable. The temperature of the remover when immersed in the remover such as the mold and jig is
From the viewpoint of safety, it is preferably between 20 ° C and 80 ° C. The reason is that if the temperature is lower than 20 ° C., the dipping time becomes relatively long in order to remove the polyurethane, and if the temperature exceeds 80 ° C., special care must be taken in handling the remover. In some removers, ultrasonic waves can be vibrated to further shorten the removal time of polyurethane.

The range of use of the polyurethane removing agent of the present invention is
Although not particularly limited, it is preferably used for removing a mold and jigs and the like to which polyurethane is attached. Here, polyurethane means a polymer obtained by polymerizing a monomer mixture containing polyisocyanate and polyol and / or polythiol. Examples of the polyisocyanate, polyol and polythiol are described in JP-A-3-28.
No. 1312, JP-A-3-236386, JP-A-1-14498 and the like are omitted. The polyurethane removing agent of the present invention is disclosed in JP-A-62 / 62.
No dangerous substances such as alkali metallized organic compounds disclosed in JP-A-243697 are used, so that the removal agent can be easily handled, and due to the synergistic effect of the essential component solution, the removal time is shorter than that of the conventional removal agent. It is possible to remove the polyurethane adhered by.

[0012]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited to these examples. (Example 1) m-xylene diisocyanate: 100 parts by weight pentaerythritol tetrakis-3-mercaptopropionate: 143 parts by weight di-n-butyl phosphate: ………………………………………… 6.05 parts by weight Dibutyltin dilauric acid …………………………………… 0.24 parts by weight 2 (2'-hydroxy-) 5'-t-octylphenyl) benzotriazole ... 0.48 parts by weight After uniformly stirring the above mixture, 3.0 g of this mixture was added.
Was applied to a glass mold and heated from 25 ° C. to 120 ° C. for 22 hours to obtain 3.0 g of polyurethane adhered to the glass mold. 40% by weight of dimethylsulfoxide (DMSO) and water 6
The removal rate of polyurethane was measured by immersing in a remover mixed with 0 part by weight and 8 parts by weight of sodium hydroxide under the condition of a remover temperature of 70 ± 2 ° C., pulling up the glass mold every 5 minutes and air drying. The results are shown in Table 1. As shown in Table 1, 22% in 5 minutes, 48% in 10 minutes, 75% in 15 minutes, 20%
It was confirmed to be a scavenger having an excellent ability of removing polyurethane by 98% in minutes. Further, no gas was found to be generated with this remover.

Example 2 Instead of 8 parts by weight of sodium hydroxide used in Example 1, potassium hydroxide 11.2 was added.
Example 1 was repeated except that the parts by weight were used. The evaluation results are shown in Table 1. As shown in Table 1, the removing agent obtained in Example 2 was as excellent in removing ability as the removing agent obtained in Example 1.

Example 3 All were the same as Example 1 except that 4 parts by weight of sodium hydroxide and 5.6 parts by weight of potassium hydroxide were used instead of 8 parts by weight of sodium hydroxide used in Example 1. Went to. As a result, as shown in Table 1, the removing agent obtained in Example 3 was as excellent in removing ability as the removing agent obtained in Example 1.

(Comparative Example 1) As an example for comparison with the removing agent of the present invention, the removing agent disclosed in JP-A-1-14498 will be mentioned. The procedure of Example 1 was repeated except that 60 parts by weight of water and 8 parts by weight of sodium hydroxide used in Example 1 were not used, and 80 parts by weight of trichlorethylene was used instead. The results are shown in Table 2. As shown in Table 2, the removing agent of Comparative Example 1 did not remove the polyurethane even after being immersed for 20 minutes.

(Comparative Example 2) Comparative Example 2 shows the removing ability of polyurethane when only DMSO is used as a removing agent. The same procedure as in Example 1 was carried out except that 60 parts by weight of water and 8 parts by weight of sodium hydroxide used in Example 1 were not used. The results are shown in Table 2. As shown in Table 2, the removing agent of Comparative Example 2 did not remove the polyurethane even after soaking for 20 minutes. The removal rates in Tables 1 and 2 were calculated by the following formula.

(Comparative Example 3) Comparative Example 3 shows the removing ability of polyurethane when DMSO is not used as a removing agent.
The same procedure as in Example 1 was carried out except that the removing agent was prepared using 100 parts by weight of water and 5.6 parts by weight of potassium hydroxide instead of 40 parts by weight of DMSO used in Example 1. The results are shown in Table 2. As shown in Table 2, the removing agent of Comparative Example 3 did not remove the polyurethane even after being immersed for 20 minutes.

(Comparative Example 4) Comparative Example 4 shows the removal ability of polyurethane when weak alkaline component potassium hydrogencarbonate is used in place of sodium hydroxide and potassium hydroxide as a removing agent. The procedure of Example 1 was repeated except that 20 parts by weight of potassium hydrogen carbonate was used instead of 8 parts by weight of sodium hydroxide used in Example 1 to prepare the removing agent.
The results are shown in Table 2. As shown in Table 2, the remover of Comparative Example 4 was such that the polyurethane was not removed even after being immersed for 20 minutes.

(Comparative Example 5) Comparative Example 5 shows the removal ability of polyurethane when weakly acidic component sodium acetate is used in place of sodium hydroxide and potassium hydroxide as a removing agent.
Indicate. The procedure of Example 1 was repeated except that 27 parts by weight of sodium acetate was used instead of 8 parts by weight of sodium hydroxide used in Example 1 to prepare the removing agent. The results are shown in Table 2. As shown in Table 2, the removal agent of Comparative Example 5 was 20
The polyurethane was not removed even after immersion for a minute.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

As described above, since the removing agent of the present invention does not generate a gas such as hydrogen, it is easy to handle, and is excellent in polyurethane removing ability as compared with the conventional removing agents.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display area B29K 75:00

Claims (1)

[Claims] 1. A polyurethane remover comprising dimethyl sulfoxide and sodium hydroxide and / or potassium hydroxide.