JPH03281248A - Repair agent and method for repairing fluororesin coating layer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a repair agent and method for repairing a fluororesin coating layer, and more specifically, a method for repairing damaged parts of a fluororesin layer coated on the surface of a base material such as steel using a resin. The present invention relates to a repair method and a repair agent used in resin repair, and particularly relates to an on-site resin repair method.

(Prior art) Fluororesins have generally excellent corrosion resistance and adhesion resistance (non-adhesion), so these properties can be used to make structural materials for equipment such as frying pans, paper rolls, chemical equipment, etc. It is widely used as a lining material (coating material) for base materials. Among them, polytetrafluoroethylene (PTFE), ie, Teflon (trade name), is widely used because of its excellent corrosion resistance and non-stick properties.

Such fluororesin coating is performed by degreasing the surface of the base material in -i,
After surface conditioning, dispersion, which is made by dispersing fluororesin particles in water with a surfactant, is sprayed onto the surface of the base material, followed by heating and baking.

However, in the case of PTFE, its melt viscosity is extremely high;
Since thermal fluidity is poor even above the melting point, microvoids are likely to remain in the PTFE coating layer. When such a PTFIi coating material is used in a solution, the solution may penetrate to the surface of the base material and corrode the base material, resulting in so-called blistering. or,
Since the PTFE coating layer is as thin as about 100 μm, it is likely to peel off during use. When such blistering or peeling occurs, the damaged area is partially repaired with PTFE coating or completely repaired (recoated). The repair/covering is performed using the same method as the fluororesin coating method, namely, coating with PTFE,
This is done by heating and baking. Incidentally, the above-mentioned phenomenon is common to fluororesins, and is also observed to a greater or lesser extent when fluororesins other than PTPE are used, resulting in the need for repair.

In recent years, various studies have been carried out to solve the above problems, and as a result, products such as tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer (PFA), etc.
Fluororesins with relatively low melt viscosities have been developed and have been used as coating materials for applications requiring non-stick properties. However, since the PFA coating layer is also thin and contains some microvoids, the occurrence of blisters and peeling cannot be completely eliminated. The damaged portion is partially repaired with PFA coating in the same manner as in the case of PTFB.

As mentioned above, the conventional fluororesin coating layer causes blistering and peeling during use and requires repair, which can be done using the same methods as the fluororesin coating method (fluororesin coating, heating, baking, etc.). ). Note that this repair is often performed on-site.

(Problem to be Solved by the Invention) However, in the above-mentioned conventional method for repairing a fluororesin coating layer, the fluororesin is heated at a relatively high temperature (for example, 300 to 400°C for PTFIE, 200°C or more for PFA). It is necessary to print, and the work is very difficult (,
There is a problem that workability is poor. This is a very serious and important problem, especially in the field, and its improvement is desperately needed.

The present invention has been made in view of these circumstances, and its purpose is to solve the above-mentioned problems, and to repair damaged parts (parts to be repaired) such as blistering and peeling of the fluororesin coating layer. The object of the present invention is to provide a repair agent and a method for repairing a fluororesin coating layer, which can repair parts of the fluororesin coating layer to be repaired such as blisters and peeling without requiring high-temperature heating.

(Means for Solving the Problems) In order to achieve the above object, the repair agent and method for repairing a fluororesin coating layer according to the present invention have the following configuration.

That is, the repair agent according to claim 1 is a repair agent that is mixed and used when repairing a fluororesin coating layer, and the repair agent includes a repair resin and a silane cup having a perfluoroalkyl group. This is a repair agent for a fluororesin coating layer, which includes a ring agent, a coupling agent having a group that binds to a repair resin, and a curing agent for the repair resin.

The repair agent according to claim 2 is a fluororesin coating according to claim 1, in which the coupling agent having the bonding group and a curing agent are mixed, and the repair resin and a silane coupling agent are mixed. It is a layer repair agent.

In the repair agent according to claim 3, the silane coupling agent is mixed in an amount of 0.1 to 100 parts by weight of the repair resin.
The repair agent for a fluororesin coating layer according to claim 2, wherein the amount is 10 parts by weight.

In the repair method according to claim 4, a repair resin, a coupling agent having a group that binds to the resin, a silane coupling agent having a barfluoroalkyl group, and a curing agent for the repair resin are mixed. This is a method for repairing a fluororesin coating layer, which comprises applying the repair agent applied to the repaired portion of the fluororesin coating layer.

The repair method according to claim 5 includes, before applying the repair agent,
5. The method for repairing a fluororesin coating layer according to claim 4, wherein an alcoholic solution or an aqueous solution of a coupling agent having a group bonding to the repair resin and a base material of the repaired part is applied to the repaired part.

The repair method according to claim 6 includes, before applying the repair agent,
The fluororesin coating according to claim 4, wherein a repair agent for undercoat, which is a mixture of a repair resin, a coupling agent having a group that binds to the resin, and a curing agent for the repair resin, is applied to the repaired area. This is a layer repair method.

In the repair method according to claim 7, after applying a repair agent containing a mixture of a repair resin, a coupling agent having a group that binds to the resin, and a curing agent for the repair resin to the repaired area, This method of repairing a fluororesin coating layer is characterized in that a repair agent containing a repair resin, a silane coupling agent having a barfluoroalkyl group, and a curing agent is applied to the coated surface.

(Function) The reason why fluororesin has Jf adhesiveness is 1. This is because it has a barfluoroalkyl group bonded to a fluorine atom in a carbon atom, and the acid group lowers the surface energy and exhibits liquid repellency (that is, non-adhesive property).

In this way, non-adhesiveness is a property only of the surface. Therefore,
When a damaged part (repaired part) of the fluororesin coating layer is repaired with a resin, the resin in the repaired part should have excellent adhesion to the base material and corrosion resistance, and the surface of the repaired part should be non-adhesive. However, it is not necessary that the interior of the resin in the repaired area be non-adhesive.

Therefore, the present invention uses the above-mentioned novel means to satisfy the above requirements and also to enable repair work without requiring high-temperature heating, thereby achieving the following objects.

That is, as described above, the repair agent for a fluororesin coating layer according to the present invention comprises a repair resin (R), a silane coupling agent (PC) having a barfluoroalkyl group, and a group that binds to the repair resin. It consists of a coupling agent (RC) having the following properties and a curing agent (H) for a repair resin, and these are mixed and used when repairing a fluororesin coating layer.

Furthermore, in the method for repairing a fluororesin coating layer according to the present invention, a mixture of the repair agents listed in "2" is applied to a portion of the fluororesin coating layer to be repaired.

There are various types of resins, and many of them, such as epoxy resins, have adhesive properties with base materials such as metals and can be cured and formed into films at relatively low temperatures in the presence of a curing agent.

In addition, there are many materials that also have excellent corrosion resistance. Therefore, when such a resin is used as the repair resin (R), the repair agent applied to the repaired area can be cured and formed into a film (synthesized) at the repaired area without requiring high-temperature heating. Moreover, the resin after the synthesis has excellent corrosion resistance.

A coupling agent having a group that binds to the repair resin (
RC) has an alkoxy group that can bond with the repair resin and easily bond with inorganic substances such as metals, so
It is possible to strongly bond, ie, couple, the repair resin and a base material such as metal. By this coupling, the adhesion between the resin synthesized in the repaired area and the base material can be extremely improved.

The silane coupling agent (PC) having a barfluoroalkyl group imparts non-adhesion to the resin synthesized in the repaired area due to the effect of reducing surface energy and improving non-adhesion of the bar-fluoroalkyl group as described above. to give. Note that the silane coupling agent and the coupling agent are dried and stabilized by heating at room temperature or low temperature, and do not require high temperature heating.

As described above, according to the repair agent or method for repairing a fluororesin coating layer according to the present invention, it is possible to repair areas to be repaired such as blistering or peeling of the fluororesin coating layer without requiring high-temperature heating. At the same time, a repaired part with excellent adhesion, corrosion resistance, and surface non-adhesion can be obtained.

The repair agent according to the present invention is used after being mixed during repair, and does not need to be mixed at all before use. That is, before use, R, PC, RC, and H of the repair agent may be in a state where they are not all mixed (each alone), or two or three of them may already be present, except when R and H coexist. They may be mixed.

For example, R, PC and RC may be mixed before use. Also, a mixture of R and PC (a), and RC
and I] (+)) may exist separately. In the latter case, (a) PC is likely to be uniformly dispersed in R, and b) RC is likely to be uniformly dispersed in IJ. Therefore, when a) and (b) are mixed during repair, PC and (b) are easily dispersed in the repair agent. RC becomes easier to be uniformly dispersed. R, R
When RC is mixed into a mixture of (or R and pc) and H,
Since the R: resin has a higher viscosity than the H: curing agent, uniform dispersion and mixing of PC becomes difficult.

The mixing ratio of the silane coupling agent (PC) is preferably 0.1 to 10 parts by weight, preferably 0.1 to 1 part by weight, per 100 parts by weight of the repair resin (R).

If it is less than 0.1 part by weight, the surface non-adhesion will be poor, if it exceeds 10 parts by weight, the adhesion to the base material will be poor, and if it is 0.1 to 1 part by weight, excellent non-adhesion and adhesion will be obtained. It becomes like this.

Before applying the repair agent, if an alcoholic or aqueous solution of a repair resin and a coupling agent having a group that binds to the base material of the repaired part is applied to the repaired part, the acid groups will further improve the adhesion to the base material. You will be able to improve.

Further, as in the repair method according to claim 6, before applying the repair agent, a repair resin (R), a coupling agent (RC) having a group that binds to the resin, and curing of the repair resin are provided. Agent (
A repair agent for undercoat mixed with the repair agent (I) is applied to the repaired area, and the repair agent (I) is applied as an upper layer on the coated surface.
When a mixture of R, PC, RC and H is coated (overcoated), the undercoat layer improves non-adhesion (i.e.
Since it does not contain PC, which degrades adhesion), it has extremely good adhesion to the base material, and for this reason, the overcoat layer may contain a large amount of PC, making it possible to further improve non-adhesion. .

As in the repair method according to claim 7, the above-mentioned undercoat repair agent (
After coating (a mixture of R, RC, and H), a repair resin (R) and a silane coupling agent (PC) having a perfluoroalkyl group are applied as an upper layer on the coated surface.
Even when a repair agent mixed with a curing agent (H) is applied (overcoated), substantially the same effects as in the case of the repair method described in claim 6 can be obtained.

The group bonded to resin:R in the above RC is, for example, an amino group in the case of resin:epoxy resin.

When an epoxy resin is used as the repair resin, the repair can be performed at a relatively low temperature, and the adhesion to the base material such as metal and corrosion resistance can be improved.

(Example) Epoxy resin as real ntL R (Araldai 1-GY250)
: 100 parts, a first repair agent formed by uniformly mixing x parts of perfluoroalkylsilane (Mitsubishi Metals: MF-160) as PC, and triethylenetetramine as H (curing agent); 12 parts , 0.3 part of aminopropyltrimethoxysilane as RC was uniformly mixed.
A repair agent consisting of a repair agent and a repair agent was used.

The first repair agent and the second repair agent are mixed in a ratio of 1:1 to prepare a repair agent for coating, and this is applied on a glass plate,
It was left to stand at 0°C for 1 hour to harden.

Next, the surface was ground with a grinder to eliminate the influence of adsorbed components, and pure water was dropped onto the surface to measure the contact angle. X
100° when x = 0.1, 120° when x = 0.5, x-1,0
140° when x=5.0, 140° when x=
When the angle was 10.0, it was 140°.

A repair agent for coating similar to that in Example 1 was applied on a 1λ iron plate (dimensions +100 x 100 x 6), and a cured resin (test piece) was prepared under the same conditions.

The non-adhesiveness of the coated surface was examined by pasting adhesive tape on the surface of the handwritten test piece (applied side) and lifting it by grasping the edge of the tape. However, x = 0
．． For the test pieces with a score of 5 or higher, the gum tape was easily peeled off from the cage, confirming that they had excellent non-adhesive properties.

A repair agent similar to that in Example 1 was applied to a J- (q3 iron plate (dimensions + 100 x 100 x 6)) and left at 50°C for 3 hours to cure (test piece). .

The repair agent (repair layer) and base 4/l (iron plate) were tested by immersing the test piece in IOO'C pure water for 10 days and periodically observing the presence or absence of peeling of the repair agent from the iron plate. The adhesion was investigated. The test piece with x = 5.0.10.0 has a repair layer of 7 and has peeled off at first glance, and the test piece with x - 0.5 or less has no peeling and has excellent adhesion to the base material. The matter was confirmed.

Implementation-4- Iron plate (dimensions: 100 x 100 x 6), J-,
An alcoholic solution containing 1% aminopropyltrimethoxysilane was applied to the area to be repaired, and after drying, a solution similar to that of X-10,0 among the coating repair agents of Example 1 was applied to the applied surface. A repair agent was applied and cured under the same conditions as in Example 3. Next, an adhesion test (10
7.11 No brocade was formed when the sample was soaked for 1 day (soaked for 1 day).

Actual difference ml iron plate (dimensions: 100 x 100 x 6) 7, epoxy resin (Araldai 1-GY250) + 100 parts,
A repair agent (undercoat) made by uniformly mixing 12 parts of a hardening agent (triethylenetetramine) and 0.3 parts of aminopropyltrimethoxysilane was applied, and the mixture was left at 50°C for 3 hours to harden. After that, a repair agent similar to that of x = ], O, O among the coating repair agents of Example 1 was applied as a top coat to the undercoat surface, and the coating was left at 50°C for 3 hours. It was hardened. Next, using this, an adhesion test similar to that in Example 3 (immersion for 10 days) was carried out, and the result was that the separation was 11 times higher than 2 times.

(Effects of the Invention) According to the repair agent or repair method for a fluororesin coating layer according to the present invention, blistering and rlIrIl of a fluororesin coating layer can be prevented.
When repairing damaged parts (parts to be repaired) such as those that require high-temperature heating (under good working conditions, parts to be repaired such as blisters and 'all separations' in the fluororesin coating layer can be repaired with resin). In addition, compared to the conventional method of applying fluororesin and baking it at high temperature, it has excellent adhesion to the base material.
In addition, a repaired part with corrosion resistance and surface non-adhesion that is equivalent to or better than that can be obtained. Therefore, a repaired part having characteristics equal to or better than that of the conventional method can be easily obtained by resin repair under favorable conditions without high-temperature heating.

Claims (7)

[Claims] (1) A repair agent that is mixed and used when repairing a fluororesin coating layer, the repair agent comprising a repair resin, a silane coupling agent having a perfluoroalkyl group,
A repair agent for a fluororesin coating layer comprising a coupling agent having a group that binds to a repair resin and a curing agent for the repair resin. (2) The repair agent for a fluororesin coating layer according to claim 1, wherein the coupling agent having a bonding group and a curing agent are mixed, and the repair resin and a silane coupling agent are mixed. (3) The repair agent for a fluororesin coating layer according to claim 2, wherein the mixing ratio of the silane coupling agent is 0.1 to 10 parts by weight to 100 parts by weight of the repair resin. (4) A repair agent containing a mixture of a repair resin, a coupling agent having a group that binds to the resin, a silane coupling agent having a perfluoroalkyl group, and a curing agent for the repair resin is applied to a fluororesin. A method for repairing a fluororesin coating layer, the method comprising applying a fluororesin coating layer to a repaired portion of the coating layer. (5) The fluororesin coating according to claim 4, wherein an alcoholic solution or an aqueous solution of a repair resin and a coupling agent having a group that binds to the base material of the repaired part is applied to the repaired part before applying the repair agent. How to repair layers. (6) Before applying the repair agent, apply a repair agent for undercoating, which is a mixture of a repair resin, a coupling agent having a group that binds to the resin, and a curing agent for the repair resin, to the area to be repaired. The method for repairing a fluororesin coating layer according to claim 4, wherein the fluororesin coating layer is coated. (7) After applying a repair agent, which is a mixture of a repair resin, a coupling agent having a group that binds to the resin, and a curing agent for the repair resin, to the area to be repaired, apply the repair resin to the applied surface. A method for repairing a fluororesin coating layer, comprising applying a repair agent containing a mixture of a silane coupling agent having a perfluoroalkyl group, and a curing agent.