JPH01224136A - Slurry mold wash and sliding material - Google Patents

Abstract

PURPOSE:To prevent the sedimentation/cohesion of a graphite at reserving time by contg. the specified wt.% of a graphite of less than specified grain diameter, the specified % of an interface active agent and the specified % of a cellulose ether and making them at specified viscosity (value at 25 deg.C). CONSTITUTION:The viscosity is adjusted to 500-15,000cps (value at 25 deg.C) as well as containing 20-40wt.% graphite of <=30mum grain diameter, 0.15-3% surface active agent and 0.1-3% cellulose ether. A flaky graphite and earthy graphite are excellent in heat resistance and corrosion resistance and heat resistance and corrosion resistance and used as a coating form and sliding materials by crushing in a proper grain size and making in a slurry by dispersing in a water. The surface active agent is necessary for dispersing a hydrophobic graphite in a water and especially nonionic surface active agent is preferable. The sedimentation/cohesion of a graphite is prevented by adjusting the viscosity of the coating form and sliding material to an optimum value by adding the cellulose ether in a proper amt. The spreading and adhesion onto a coating face are thus good without causing any sedimentation/cohesion at graphite reserving time and the coating face excellent in slidability can be formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides coating materials and sliding materials based on graphite that are in the form of a slurry in which graphite does not settle or aggregate during storage. It is related to.

[Prior art] Graphite such as scaly graphite and earthy graphite has excellent heat resistance and corrosion resistance, so it is crushed to an appropriate particle size and dispersed in water to form a slurry, which is used as a coating material and sliding material. ing.

Furthermore, 5i02, AI, O,
, MoS, , BN, and other inorganic substances, and organic compounds such as polytetrafluoroethylene, oxybenzoyl polyester, fluororesins, thermoplastic aromatic polyethers, aromatic polyether ketone resins, and fluorocarbon polymers are used as binders or other additives. It is mixed as.

Since graphite is hydrophobic, it is commercially available in the form of a powder that has been treated with a surfactant to give it wood-philic properties, or as a slurry with a graphite concentration of approximately 30% that has been dispersed in water using a surfactant. However, in the former case, the graphite tends to aggregate and form lumps during storage, and in the latter case, the graphite tends to settle and aggregate, and in both cases, the mold is mixed with the coating material and the sliding material. and poor agitation when applying to refractory bricks.

This causes problems such as poor spreading and poor adhesion, as well as defects in the coating film and poor sliding properties of the coated surface.

[Problems to be Solved by the Invention] Concerned about this situation, the inventors of the present invention conducted studies and found a separate solution to the defects in storing the product in powder form, and filed a patent application. In the present invention, we studied coating materials and sliding materials that do not cause the above-mentioned problems because graphite does not settle or aggregate in the lower layer during storage when provided in the form of a slurry.

[Means for Solving the Problems] The slurry coating material and sliding material of the present invention that can solve the above problems are based on graphite, and include (A) graphite with a particle size of 30 μm or less: 20 -40% (B) surfactant: 0.15-3% (C) cellulose ether: 0.1-3%, and has a viscosity of 500-xsooocps.

[Function] As the base material in the coating material and sliding material of the present invention, flaky graphite or globular graphite, whether natural or synthetic, can be used. In this case, the particle size of graphite must be 30 μm or less; if it exceeds 30 μm, the influence of particle growth due to aggregation will become noticeable, and sedimentation will easily occur. is 20 to 40%.

If the graphite concentration is less than 20%, the graphite concentration will be too low and its function as a coating material and sliding material will be insufficient, and the viscosity will be insufficient, resulting in paint dripping and uneven coating.On the other hand, if it exceeds 40%, the graphite concentration will be insufficient. If the concentration is too high, agglomeration and sedimentation of graphite tend to occur, and painting workability becomes worse.

The surfactant is a necessary component for dispersing hydrophobic graphite in water, and any of cationic, anionic, nonionic, and amphoteric surfactants can be used freely as long as they do not cause significant foaming. However, in the sense of dispersing hydrophobic substances such as graphite in water, it is desirable to use nonionic surfactants. For example, fatty acid esters of polyoxy compounds (polyols), polyethylene oxide condensates, etc. are used as nonionic surfactants. Can be mentioned. And the amount added needs to be 0.15 to 3%,
If it is less than 0.15%, the dispersibility of graphite will be difficult, and if it exceeds 3%, the dispersibility effect of graphite will not be improved, and there is a risk of foaming.

The cellulose ether used in the present invention is the OH of cellulose.
A compound in which part or all of the group is etherified,
Methylcellulose, ethylcellulose, hydroxyethylcellulose, methylhydroxyethylcellulose, carboxymethylcellulose, etc., and mixtures thereof can be used.

In the present invention, by adding cellulose ether, the viscosity of the mold coating material and sliding material can be adjusted to 500 to 15,000.
cps is adjusted to prevent sedimentation and agglomeration of graphite, but if the viscosity of the coating material and sliding material is less than 500 cps, sedimentation and aggregation of graphite will easily occur;
If it exceeds s, problems will occur in stirring performance and coating workability when preparing coating material and sliding material.

In order to keep the viscosity of the coating material and sliding material within the above-mentioned preferred range, the amount of cellulose ether added should be 0.1 to 3%.
Preferably it needs to be 0.2 to 1%.

Furthermore, bentonite, clay, and the above-mentioned inorganic and organic substances can be added to the coating material and sliding material of the present invention within a range that does not impede the effects of the present invention.

[Example] Example 1 300 g of graphite with a particle size of 5 to 7 μm was mixed with a nonionic surfactant (
700 g of water with 10 g of polyethylene oxide condensate)
g, and further added 10 g of methylcellulose (viscosity of 1% aqueous solution: 3000 cps) to make the viscosity 5000 cps.
A cps slurry coating material and sliding material were obtained.

No sedimentation of graphite was observed even after the obtained coating material and sliding material were left for 10 days. When the coating material and sliding material were applied with a brush to the surface of the mold and firebrick, a good coating film was obtained, and the coating film was subjected to the ** test and heating test specified in JIS-5400. As a result, no dents, bubbles, bulges, cracks, or peeling were observed.

Example 2 300 g of graphite with a particle size of 1 to 3 μm was mixed with a nonionic surfactant (
700 g of water with 10 g of polyethylene oxide condensate)
g, and further carboxymethyl cellulose (1
% aqueous solution (viscosity 300 cps) was added to obtain a slurry coating material and sliding material having a viscosity of 3000 cps.

No sedimentation of graphite was observed even after the obtained coating material and sliding material were left for 10 days. When the coating material and sliding material were spray applied to the surface of the mold and firebrick, a good coating film was obtained, and the coating film was rated according to JIS-5400.
When we conducted an impact test and a heating test, we found that there were dents,
Bubbles, blisters.

No cracking or peeling occurred.

Example 3 300 g of graphite with a particle size of 5 to 7 μm was mixed with a nonionic surfactant (
Using 10 g of polyethylene oxide condensate, add 70 g of water.
08 and further added 5 g of methyl hydroxyethyl cellulose (viscosity 4000 cps when 1% aqueous solution) to obtain a slurry coating material and sliding material having a viscosity of 4000 cps.

No sedimentation of graphite was observed even after the obtained coating material and sliding material were left for 10 days. When the coating material and sliding material were brushed onto the surface of the mold and firebrick, a good coating film was obtained, and the coating film was rated W of -5400 according to JIS-5.
When a one-shot test and a heating test were conducted, no dents, bubbles, blisters, cracks, or peeling occurred.

Example 4 300 g of graphite with a particle size of 1 to 3 μm was mixed with a nonionic surfactant (
10g of polyethylene oxide condensate) and water OO
g and further dispersed in hydroxyethyl cellulose (1
% aqueous solution (viscosity 250 cps) was added to obtain a slurry coating material and sliding material having a viscosity of 2000 cps.

No sedimentation of graphite was observed even after the obtained coating material and sliding material were left for 10 days. When the coating material and sliding material were sprayed onto the surfaces of molds and refractory bricks, a good coating film was obtained, and the coating film was rated according to JIS-540.
When an impact test and a heating test were conducted, no dents, bubbles, blisters, cracks, or peeling occurred.

Comparative Example 1 300 g of graphite with a particle size of 5 to 7 μm was mixed with a nonionic surfactant (
700 g of water with 10 g of polyethylene oxide condensate)
g to obtain a slurry coating material and sliding material having a viscosity of 100 cps.

When the obtained coating material and sliding material were left for 24 hours, graphite settled in the lower layer.

Comparative Example 2 300 g of graphite with a particle size of 5 to 7 μm was mixed with a nonionic surfactant (
10 g of polyethylene oxide condensate) was dispersed in 700 g of water, and 10 g of polyvinyl alcohol with a molecular weight of t 500 was added to give a viscosity of 20,000 cp.
A slurry coating material and sliding material of s were obtained.

When the obtained coating material and sliding material were left for 24 hours, graphite settled in the lower layer.

Comparative Example 3 300 g of graphite with a particle size of 15 to 20 μm was dispersed in OOg of water using 10 g of a nonionic surfactant (polyethylene oxide condensate), and 10 g of yellow dextrin was further added to form a slurry-like coating material with a viscosity of 200 cps. and sliding material was obtained.

When the obtained coating material and sliding material are left for 24 hours, the graphite settles in the lower layer. When the film was subjected to JIS-5400 ** test, dents appeared and it was roughly JIS-540.
When a heating test of 0 was conducted, one bubble broke.

[Effects of the Invention] Since the present invention is configured as described above, the coating material and sliding material of the present invention do not cause sedimentation or agglomeration of graphite during storage, and therefore do not spread on the coated surface. It has good properties and adhesion, and also forms a coated surface with good coating properties and excellent sliding properties.

Claims (1)

[Claims] In coating materials and sliding materials based on graphite, (A) graphite with a particle size of 30 μm or less: 20 to 40% (wt%);
(the same meaning hereinafter) (B) Surfactant: 0.15 to 3% (C) Cellulose ether: 0.1 to 3% and has a viscosity of 500 to 15,000 cps (25
A slurry-like coating material and sliding material characterized by having a value at °C (the same applies hereinafter).