JPH02261899A - Polyurethane remover - Google Patents

Abstract

PURPOSE:To obtain a polyurethane remover free from the problem of corrosion of a device for the manufacture of molded polyurethane articles and improved in the capability of peeling polyurethane by mixing organic solvents and specified compounds. CONSTITUTION:20 to 70vol.% of one or more organic solvents selected from halogenated hydrocarbon (e.g. methylene chloride) and aromatic hydrocarbon (e.g. benzene) are mixed with 70 to 20vol.% compounds of formula I and/or II (wherein X1 is 0 or S; X2 is 0, S or sulfonyl; R1 is H, methyl, aldehyde or carboxyl; R2 is H, methyl or carboxyl; (n) is 4 to 6).

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a polyurethane remover that firmly adheres to molds made of glass, metal, etc., especially when manufacturing polyurethane molded products such as polyurethane lenses. The present invention relates to a polyurethane remover suitable for removing polyurethane.

[Prior art and its problems] In the production of polyurethane molded products, if polyurethane remains in the mold after the resulting polyurethane molded product is released from the mold, it may affect the mold assembly and transferability of the mold in the next molding operation. Problems arise and it becomes impossible to obtain a molded product with the desired shape.

Therefore, polyurethane remaining on the mold is removed physically or mechanically, but with mirror-finished molds that require precise transferability, scratches are a problem, and this problem is caused by the material. This is particularly serious for molds made of glass or other materials with low surface hardness.

Therefore, as a chemical method for removing polyurethane, for example, strong acids such as concentrated sulfuric acid and concentrated nitric acid are used. etc. may also corrode. Although considerable effects have been recognized by changing the materials used to prevent corrosion, it is not perfect, and there are cases in which it is difficult to incorporate complex mechanisms into equipment. Furthermore, the use of acid-resistant equipment results in an increase in equipment costs.

Additionally, unnecessary polymers are removed from molds using solvents with high polymer solubility, such as methylene chloride, dichloroethane, carbon tetrachloride, trichlorethylene, perchlorethylene, and various aromatic compounds. Although this method is easier in terms of equipment than when using the above-mentioned strong acid, the polymer to be removed is
In the case of polyurethane, etc., which has a high 5 degree and strong adhesive properties, it cannot be peeled off and removed in a short time.

Generally, a mixture of methylene chloride and a strong acid is used as a stripping agent for polyurethane and epoxy paints, but since it contains a strong acid, there remains the problem of corrosion of equipment. Furthermore, there are stripping agents that contain phenol to strengthen stripping power while reducing corrosiveness, but as is well known, phenol is acutely and chronically toxic and has a negative impact on the working environment and external environment. Prevention equipment requires a large amount of money.

The purpose of the present invention is to eliminate the drawbacks of the conventional polyurethane remover mentioned above, to provide a polyurethane removal agent that has excellent polyurethane peeling force, and that does not cause corrosive problems for manufacturing equipment for polyurethane molded products.
An object of the present invention is to provide a new polyurethane removing agent.

[Means for Solving the Problems] The present invention has been made to achieve the above object, and the polyurethane removing agent of the present invention comprises a flIWI medium and a general formula (I) (where x1 is an oxygen atom or It is a sulfur atom, and R1
is hydrogen, a methyl group, an aldehyde group, or a carboxyl group, and R2 is a compound voice and/or a general formula <ff) represented by hydrogen, a methyl group, or a carboxyl group,
n is an integer from 4 to 6. ) It is characterized by containing the compound represented by.

The present invention will be explained in detail below.

As the organic solvent used in the present invention, halogenated hydrocarbons are preferably used, and representative examples thereof include methylene chloride, trichloroethylene, perchloroethylene, 1.1
．． Examples thereof include 1-trichloroethane, but of course the present invention is not limited to these. Aromatic hydrocarbons can also be used as organic solvents, typical examples of which include benzene, toluene, xylene, etc., but of course the solvent is not limited to these. These organic solvents are not limited to the same kind. Two or more of these organic solvents may be of the same type (halogenated hydrocarbons or aromatic hydrocarbons) or different types (halogenated hydrocarbons and aromatic hydrocarbons).

Further, the compounds of general formula (I) used in the present invention include furan, furfural, 2-methylfuran, 3-methylfuran, 2-furancarboxylic acid, 3-furancarboxylic acid, thiophene, 2-methylthiophene, Examples include 2-thiophenecarboxylic acid and 3-thiophenecarboxylic acid.

Furthermore, compounds of general formula (I[) used in the present invention are included. These compounds represented by general formula (I) and/or general formula (I) may be used alone or in combination of two or more.

Organic solvent/- general formula I) and/or general formula (II)
The ratio of the compounds represented by can be varied over a wide range in terms of volume ratio, but a particularly preferred ratio is 20/70 to 20/70.
It is 7o/20.

The polyurethane removing agent of the present invention can contain other additives as necessary in addition to the compound represented by the general formula (1) and the organic solvent. Examples of these include surfactants such as alkylbenzene sulfonates, α-olefin sulfate ester salts, alcohol sulfate ester salts, alcohol ethylene oxide adducts, and fatty acid jetanolamide;
Examples include salts such as sodium phosphate and sodium silicate; amines such as pyridine, triethanolamine, and triethylamine; and polyhydric alcohols such as glycerin and ethylene glycol.

Examples of the polyurethane that can be removed by the removing agent of the present invention include polyurethanes obtained by reacting polyisocyanates with polythiols or polyols.

The polyisocyanate used to obtain the above polyurethane is not particularly limited, but includes tolylene diisocyanate, diphenylmethane diisocyanate, Polymec type diphenylmethane diisocyanate, naphthylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylene diisocyanate, hydrogenated xylene diisocyanate, water Added diphenylmethane diisocyanate, lysine diisocyanate, triphenylmethane triisocyanate, tris(isocyanatephenyl)thiophosphate, trans-cyclohexane 1,4-diisocyanate, p-phenylene diisocyanate, tetramethylene diisocyanate, 1
．． 6.11-Undecane triisocyanate, 1.8-
Polyisocyanate compounds such as diisocyanate-4-isocyanate methyl octane, lysine ester triisocyanate, 1.3.6-hexamethylene triisocyanate, bicyclohebutane triisocyanate, and 70-fanet modified products and billet modified products of these compounds, Examples include isocyanurate modified products, adduct modified products with polyols or polythiols, etc., and they may be used alone or as a mixture of two or more types as required.

Other known isocyanate compounds may be used, but the isocyanate compound serving as the main component must be bifunctional or higher. A halogen atom such as OL or 3r may be introduced into a known aromatic isocyanate compound. Particularly preferred isocyanate compounds include non-yellowing type isocyanate compounds represented by xylene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate.

Furthermore, the polythiol used in the reaction with the polyisocyanate is not particularly limited, and any known polythiol can be used. For example, ethanedithiol, propanedithiol, propanedithiol, butanedithiol,
Pentanedithiol, hexanedithiol, heptanedithiol, octanedithiol, cyclohexanedithiol, cyclohebutanedithiol, 2,5-dichlorobenzene-1,3-dithiol, pentaerythritol tetrakis 3-mercaptopropionate, pentaerythritol tetrakis thioglyco Among them, pentaerythritol derivatives are particularly preferred.

The polyol is not particularly limited, but propylene glycol, glycerin, hexanetriol, diglycerin, pentaerythritol, polyethylene and the like are preferred.

The polyurethane remover of the present invention is used as follows. That is, the mold and tools to which polyurethane is attached are immersed in a polyurethane remover. Removal of the polyurethane may be facilitated by ultrasonic vibration during soaking. Further, the polyurethane remover of the present invention may be applied only to the portions of the mold and tools to which polyurethane is attached.

As is clear from the Examples described below, the polyurethane remover of the present invention not only has excellent polyurethane peeling power but also has the advantage of not having metal corrosion properties.

In addition, in the polyurethane remover of the present invention, polyurethane is removed by peeling rather than dissolving it, so it is easy to separate polyurethane from the polyurethane remover after peeling treatment, and the service life of the polyurethane remover is also shortened. Not only can it be used repeatedly for a long time, but it also has the advantage that it can be easily recovered by distillation or the like.

[Examples] Examples of the present invention are shown below, but the present invention is not limited to these Examples.

In addition, various physical properties of the polyurethane removing agents obtained in Examples and Comparative Examples were measured by the following test methods.

U, S,: Ultrasonic imaging (Yamato Chemical, Plansonic)
220) Peelability Polyurethane adhered to Nigaras Metal (SU3304) was immersed in a remover for 2 minutes to evaluate the peeling state of the polyurethane.

◎ Particularly excellent.

○ Excellent.

△ Partial peeling.

× hardly peels off.

Metal corrosivity: Metal immersed in a remover for one day (SU330
4) The change in surface gloss was evaluated.

○ No change △ Loss of gloss × Change to black (Example 1) m-xylene diisocyanate, 100 g
Pentaerythritol tetrakis 3-mercaptopropionate・・・143g Di-n-butyl phosphate・・・・・・・・・・・・・・・・・・
...6.05y dibutyltin dilauric acid...
・・・・・・・・・・・・0.24g2(2′-hydroxy-5”-t-octylphenyl)benzotriazole・・・・・・・・・
・・・・・・・・・・・・・・・・0.48g After stirring the above mixture uniformly, it was placed in a mold consisting of a resin gasket and a glass mold, and heated from 25℃ to 120℃ for 22 hours. A polyurethane molded article was obtained by heating. On this occasion,
The polyurethane in the form of water droplets adhering to the outside of the glass mold and the jigs and the polyurethane in the form of a thin film formed near the contact surface between the glass mold and the resin gasket are mixed with furan, which is a compound of general formula (I), and methylene chloride in a volume ratio. It was immersed in a remover mixed at a ratio of 2:1 to observe the peeling state of polyurethane and metal corrosiveness. The results are shown in Table 1.

(Examples 2 to 9) In the same manner as in Example 1, adhesive-curing polyurethane was prepared using the general formula (
1) and the peeling state of polyurethane and metal corrosiveness by immersing it in a remover that is a mixture of various compounds represented by the general formula (ff) and various solvents. IA guessed. In addition, Example 2
In Examples 3 to 9, ultrasonic vibration was applied unlike in Example 1, although ultrasonic imaging was not applied as in Example 1.

The results are shown in Table 1.

(Examples 10 to 12) A polyurethane molded article was obtained in the same manner as in Example 1, except that 0.01 g of polyethylene glycol (average molecular weight: 200) was further added to the seven-mer mixture of Example 1. At this time, the polyurethane that has adhered and hardened to the glass mold and tools is immersed in a removal agent that is a mixture of compounds represented by general formulas (I) and (I[) and various solvents, and subjected to ultrasonic imaging. What is the peeling state of polyurethane and metal corrosion? 112
I guessed it.

The results are shown in Table 1.

(Comparative Examples 1 to 8) Same as Example 1 except that a polyurethane remover other than the polyurethane remover of the present invention was used,
Adhesive and hardened polyurethane was immersed and subjected to ultrasonic vibration to observe the peeling state of the polyurethane and metal corrosion. The results are shown in Table 2.

(The following is a blank space) According to Tables 1 and 2, the polyurethane remover of this example is superior in polyurethane removal properties to the conventionally known ones shown in Comparative Examples 1 to 7.

Furthermore, the conventionally known remover shown in Comparative Example 8 has excellent polyurethane stripping properties but is highly corrosive to metals, and from this point as well, the remover of this example, which is not corrosive to metals, is superior.

Furthermore, as is clear from Examples 1 and 2, the polyurethane remover of the present invention is also excellent in that polyurethane can be removed to a satisfactory degree even without applying ultrasonic vibration.

[Effects of the Invention] As described above, the polyurethane remover of the present invention can effectively remove polyurethane from molds and jigs with complex shapes, and prevents corrosion of molds, jigs, and their auxiliary equipment and equipment. It can be used without.

Claims (2)

[Claims] (1) Organic solvents and general formulas (I) ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) (However, X_1 is an oxygen atom or a sulfur atom, and R
_1 is hydrogen, a methyl group, an aldehyde group, or a carboxyl group, and R_2 is hydrogen, a methyl group, or a carboxyl group. ) and/or general formula (II) ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (II) (However, X_2 is an oxygen atom, a sulfur atom, or a sulfonyl group, and n is an integer from 4 to 6. .) A polyurethane removing agent characterized by containing one or more types of compounds represented by the following. (2) The polyurethane removing agent according to claim 1, wherein the organic solvent is a halogenated hydrocarbon, an aromatic hydrocarbon, or a mixture thereof.