JPS5832612A - Low-viscosity organic impregnating agent and its impregnation - Google Patents

Abstract

PURPOSE:To improve water resistance and workability, by impregnating a porous part with the titled impregnating agent obtained by adding proper amounts of a polymerization initiator and a polymerization inhibitor to a mixed system of a hydrophilic (meth)-aryclic acid ester monomer and a hydrophobic (meth)acrylic acid ester monomer. CONSTITUTION:0.2-4wt% coupling agent and 100-1,000ppm polymerization inhibitor and 1.5-3wt% polymerization initiator (e.g., benzoyl peroxide) are added to a given amount of an acrylic acid or methacrylic acid ester (the solubility of the impregnating solution is in a range of 5-30wt%) (e.g., methacrylic acid 2-hydroxylmethyl) having at least one hydrophilic functional group and a given amount of a hydrophobic acrylic acid or methacrylic acid ester (e.g., methyl methacrylate) to give the desired impregnating agent. A porous part is impregnated with the agent by preferably evacuation/immersion/compression (B process), it is saturated with the impregnating solution, and the impregnated part is washed with a cleaning water. EFFECT:Improved solvent resistance and chemical resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for impregnating a low-viscosity organic impregnating agent into defective pores, pores, voids, etc. of metal castings and sintered bodies, or into pores, etc. of non-metal molded bodies. be.

The use of impregnation treatment was to improve productivity by correcting defects in products or raw materials. However, as the application of impregnation treatment expands, there is a tendency that quality control and improvements in mechanical and chemical performance are required rather than impregnation treatment. Along with this, conventional impregnating agents are no longer satisfactory, and advanced impregnating techniques have become necessary.

In the electrical engineering industry, highly viscous impregnating agents such as epoxy resins and phenolic resins have been used.

On the other hand, inorganic impregnation agents such as water glass, colloidal silica, and alumina sol have been used for cast products and sintered products. . Since impregnating agents cannot be used unless they are liquid, these inorganic impregnating agents contain at least 50% water. Curing is accomplished by the loss of moisture in the impregnating agent.

Therefore, there is always a large shrinkage, and the impregnation effect is never satisfactory.

Initially, polyester resin,
Diaryl phthalate resin etc. have been used. However, these impregnating agents have high viscosity and contain styrene monomer, so they have problems with odor and poor workability, so they are not used much these days. Recently, methacrylic acid ester monomers have been used as impregnating agents because of their low viscosity. In 49-35058, methacrylic acid ester was used as an impregnating agent by taking advantage of its anaerobic properties. Organic solvents are used for cleaning after impregnation. It is dangerous to work with, and the cleaning solvent stains very quickly. Since it is anaerobic, it is not possible to create a sufficient degree of vacuum to replace the impregnating agent with the air in the defective pores of the object during the impregnation process, and the impregnation effect is not good.

For impregnation using a weakly anaerobic methacrylic ester monomer, it is characterized by containing several percent of a surfactant in the methacrylic ester monomer, as described in No. 55-46644. Polymerization by adding several percent of a surfactant to an impregnating agent consisting of a methacrylic acid ester monomer generally improves adhesion to metals.
``-71'' It is always bad (may be, it may not be completely polymerized) (・There is one drawback. By cleaning the impregnant that adhered to the object to be impregnated in the cleaning process after impregnation, the methacrylic acid ester monomer is added to the cleaning tank. The high concentration of surfactant causes IJ cleaning failure, so the cleaning water needs to be replaced frequently.In addition, the cleaning water has a high BOD force, so wastewater treatment lowers the BOD to the standard value. It cannot be less than that.

When these impregnating agents are used for impregnating a sintered body, it has good affinity with IJ water due to the inclusion of a surfactant (the surface of the sintered body is washed too much, and as a result, Pressure leakage occurs through the surface layer of the sintered body when a pressure leakage test is performed after curing. This has made it possible to create an innovative impregnating agent and method that is highly resistant to water, has good workability in the impregnating process, and does not require wastewater treatment.

The present invention was developed as a result of repeated research to achieve the above objectives.
An acrylic ester or methacrylic ester having at least one hydrophilic functional group is used, and the solubility of the acrylic ester or methacrylic ester monomer or oligomer in water is in the range of 5 to 30. It is characterized by Furthermore, examples of the hydrophobic hexamer include acrylic acid ester and methacrylic acid ester. Appropriate amounts of a polymerization initiator and a polymerization inhibitor are added to a mixed system of these hydrophilic and hydrophobic hexamers to prepare an impregnating agent.

The hydrophilic acrylic acid and methacrylic acid used in the present invention include 2-hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate.

Dimethyl methacrylate amino ether, dimethyl methacrylate 7-minoethyl methyl chloride, methoxypolyethylene glycol methacrylate.

These are methacrylic acid esters and their acrylic acid esters, such as ethyrezoglycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and polyethylene glycol methacrylate.

Hydrophobic monomers include polypropylene glycol monomethacrylate, methyl methacrylate, and ethyl methacrylate.

n-butyl methacrylate, isobutyl methacrylate, tertiary butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, alkyl methacrylate, tridecyl methacrylate.

Allyl methacrylate and its acrylic acid ester such as stearyl methacrylate, cyclohexyl methacrylate, diethylaminoethyl methacrylate, ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, trimethylolpropane trimethacrylate, allyl methacrylate, etc. be. These hydrophilic monomers and oligomers are blended with hydrophobic monomers and oligomers to reduce surface tension and improve adhesion to metals.
Use appropriate amounts of coupling agent, titanium force, and pulling agent.

In order to improve the stability during storage, a polymerization inhibitor is added at a concentration of 100 to 1000 ppm.

Polymerization initiators include azobisisobutyronitrile, hendiyl peroxide, tert-butyl peroxybenzoate, lauryl peroxide, tert, t-butyl peroxyisobutyrate, tert-butyl peroxy acetate, bird's tyl peroxy biparate. , methyl ethyl ketone peroxide.

These include octatool peroxide, decanoyl/<-oxide, stearyl-oxide, dicumyl peroxide, cumenoyl peroxide, and decanoyl/<-oxide.

The above polymerization initiator is blended in a proportion of 1.5 to 3% at the time of use and used as an impregnating agent.

According to the present invention, the viscosity can be freely changed from 5 centipoise to 507 centipoise by changing the blending ratio of the hydrophilic monomer and the hydrophobic monomer. The impregnating effect can be improved by using a small impregnating agent and, for objects to be impregnated with relatively large defect pores, by using an impregnating agent with a high viscosity.

Next, the impregnation process will be explained: (1) Vacuum-immersion-pressure method (generally called method B) (2)
Vacuum-immersion method (3) Immersion-vacuum method (4) Internal pressure method (generally called method A) (5) Immersion pressure method (6) Immersion method (also called dipping method) Impregnation using methods Gt (1), , and (4) specified in IJ, MIL-8TD-276 provides the best impregnation effect.

After impregnating castings and sintered bodies of aluminum alloys, iron alloys, etc. with the impregnating liquid according to the present invention using the method (1) above, the impregnating liquid adhering to the surfaces is washed away. There is a process from the bottom - 61 The basket filled with the material to be impregnated is moved up and down repeatedly using a hoist to thoroughly clean the surface. Normally, the impregnating liquid on the surface of the sintered body is washed away. This tendency is particularly strong when the impregnating agent contains a surfactant. In the cleaning step after impregnation using the impregnating agent of the present invention, since a part of the composition of the impregnating agent is hydrophilic, it dissolves in water and can cleanly clean the surface of the object to be impregnated. The washed-off impregnating agent is partially dispersed and partially dissolved in the washing water.

This dissolved ratio is the same as the solubility of the impregnating agent, and the washing water is saturated with the impregnating agent. The dispersed impregnating agent has a higher specific gravity than water, so it settles out in a few minutes. The concentration of the impregnating agent in the washing water repeatedly changes from saturated to supersaturated to saturated during the washing process. The excess impregnating agent washed away in this way settles and collects at the bottom of the washing tank. Double-layer the bottom of the washing tank as shown in the figure to prevent the impregnating agent accumulated at the bottom from rolling up during washing. There is a pipe at the bottom of the washing tank that collects the impregnating agent at the bottom, and by opening the pulp, the difference in liquid level with the washing water makes it easy to take out the impregnating agent that has been washed away. .

With this cleaning method, the cleaning water in the washing tank is free of impregnating liquid contamination below a certain level, and there is no need for cleaning defects, and furthermore, there is no need to drain the cleaning water.

After washing, the object to be impregnated is heated and hardened by immersing it in hot water at 90° C. for 5 minutes or more.

Next, the present invention will be explained by examples.

Example 1 70 parts by weight of 2-hydroxypropyl methacrylate 20 parts by weight of 1,3-butylene glycol dimethacrylate Polymerization inhibitor 0.04 parts by weight Polymerization initiator 2.0 parts by weight Example 2 Methoxypolyethylene glycol methacrylate
75 parts by weight Neopentyl glycol dimethacrylate 25 parts by weight Polymerization inhibitor 0.05 parts by weight Polymerization initiator 2.0 parts by weight Aluminum castings were treated with MIL-8TD-2 using the impregnating agent according to Examples 1 and 2.
It is impregnated by method B shown in No. 76, and after washing, it is immersed in hot water at 90°C. After about 10 minutes, take it out,
The impregnation effect was confirmed by a pressure test at an air pressure of 5°6 kg/cr/I, and the result was a 100% pass. It also passed the pressure test 100% after various tests as shown in MIL-I-6869.

Example 3 70 parts by weight of 2-hydroxypropyl methacrylate 20 parts by weight of neopentyl glycol dimethacrylate Silane coupling agent 1 part by weight Polymerization inhibitor 0.04 parts by weight Polymerization initiator
2 parts by weight Example 4 2-hydroxypropyl methacrylate 70 parts by weight Neopentyl glycol dimethacrylate 20 parts by weight Titanium coupling agent 1 part by weight Polymerization inhibitor 0.04 parts by weight Polymerization initiator
2 parts by weight Example 5 Dimethylaminoethyl methacrylate 75 parts by weight Trimethylol bronotrimethacrylate (725 parts by weight Titanium coupling agent 1 part by weight Polymerization inhibitor 0.04 parts by weight Polymerization initiator
Using 2 parts by weight of the impregnating agents of Examples 3 to 5, 100 ring-shaped iron sintered bodies were each prepared by impregnation method B.
As a result of the pressure leakage test according to the test method of MIL-I-6869, the impregnation effect was 100%, <-cents. Furthermore, when the radial crushing strength of the rings after impregnation was examined, an increase in strength of 20 percent or more was obtained in all cases.

The interval between the first impregnation step and the second impregnation step is 20 minutes or more. The specific gravity of the impregnating agent in each example is in the range of 1.015 to 1.04, and the impregnating agent that has been thoroughly washed settles to the bottom of the washing tank in 20 minutes.

Carbon molded at a pressure of 2ookg/cl was impregnated by method B using the impregnating agents of Examples 3 to 5.

When the compressive strength of this carbon was measured, it was found that the strength increased by more than 1.8 times.

However, the impregnation method carried out according to the present invention has a sufficient impregnation effect, and does not require waste water treatment of washing water unlike general factory wastewater, so it is an innovative method that is widely used in the foundry industry, sintering industry, and other industries. It can be provided to non-metal molded bodies, etc.

[Brief explanation of drawings]

Fig. 1 is a plan view of a washing tank according to the present invention, and Fig. 2 is a front view. Piping C・
...Basket support stand 2@

Claims (1)

[Scope of Claims] 1. It is characterized by consisting of a water-soluble acrylic acid or methacrylic acid 7-1-ester monomer and a weakly soluble or insoluble acrylic acid or methacrylic acid ester monomer, which has a polymerization inhibitor. Method 2 of impregnating a porous body using a low-viscosity organic impregnating agent prepared by adding an appropriate amount of a polymerization agent and a polymerization initiator, Claim No. 2 characterized in that the solubility of the impregnating liquid is in the range of 5 to 30%. Impregnation method 3 according to claim 1. After impregnation, method 4 in which the object to be impregnated is washed with washing water saturated with the impregnating liquid according to claims 1 and 2. Coupling agent 0.2 to 4% is added. Claim 1
Impregnating agent characterized by being added to the impregnating liquid of Items 1 and 2.