JPH03287675A - Resin composition for peeling paint dust - Google Patents

Abstract

PURPOSE:To form the title composition excellent in rustproofness, the effectiveness in peeling off paint dust, durability, etc., by using a specified organopolysiloxane resin as a principal resin component. CONSTITUTION:An organopolysiloxane resin of the formula (wherein R is H or a monovalent organic group bonded to an Si atom through a C-Si linkage; R' is H, 1-20C alkyl, acyl, aryl or an oxime residue; m and n are each a number below 4, provided that m+n is below 4) is used as a principal resin component and preferably mixed with an alkali metal compound (e.g. LiF) to produce the title composition. When this composition is applied to a hanger, a coating booth, etc., before coating, the paint deposited on the hanger, coating booth wall, etc., during coating can be readily peeled off by merely pulling it mildly by the hand.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention prevents corrosion of paint booths, hangers and trolleys on which objects to be coated are suspended or placed on painting lines, etc. This invention relates to a resin composition that can easily remove paint (dust) adhering to the walls of a paint booth, hangers, etc. during the painting process.

[Prior art and its problems] In the painting process on a painting line, etc., the objects to be coated are usually first hung on hangers or placed on trolleys, and then subjected to surface treatment and painting (e.g., electrocoating, static coating, etc.). It consists of the following steps: bottom, middle, and top coating (electronic coating, spray coating, dip coating, etc.) and drying (baking). A new object to be coated is attached to the hanger or cart and the above process is repeated again. Therefore, in such a painting line, hangers and trolleys are used repeatedly and the painting-drying process is cycled many times, so paint is coated on these hangers and trolleys, and it gradually accumulates, increasing its thickness. Since the thickness reaches 3 to 4 mm or more, it is necessary to peel and remove it regularly.

Traditionally, thick coatings applied to hangers, etc., were scraped off with a hammer or spatula, or removed by shock blasting, but because of their excellent adhesion, they cannot be removed easily. .

Additionally, if hangers and the like are left unused before use or after the coating has been peeled off, rust may develop and corrosion may progress, reducing strength.

Furthermore, paint dust gradually accumulates on the walls of the painting booth where electrostatic painting, spray painting, etc. are performed, forming a thick coating that must be peeled off periodically.

Therefore, the present inventors have developed a resin composition that can easily peel off and remove the above-mentioned thick coatings applied to hangers, paint booth walls, etc., and that also forms a coating that prevents the formation of rust. As a result of conducting research for the purpose of developing this, it was discovered that a film formed from a composition containing a specific organopolysiloxane resin as the main resin component has the above performance, and the present invention was completed. .

That is, the present invention uses the unit formula R7Si (OR').

0(4-ゎ-n7□ [In the formula, R represents a monovalent organic group bonded to silicon through a carbon-silicon bond or a hydrogen atom, R' represents a hydrogen atom, an alkyl group or an acyl group of 01 to .. , represents an aryl group or an oxime residue, where n and m
are each a numerical value less than 4, and n+m is less than 4.

The present invention relates to a resin composition for removing paint dust containing an organopolysiloxane resin represented by the following as a main resin component.

The organopolysiloxane resin in the present invention is represented by the above-mentioned unit formula % and can be dispersed and/or dissolved in water and an organic solvent to form a liquid state. R in the above formula is a monovalent organic group bonded to silicon via a carbon-silicon bond or hydrogen.

Examples of the organic group include methyl, ethyl, propyl,
Alkyl groups such as hexyl; cycloalkyl groups such as cyclohexyl, cyclobutyl, cyclopentyl; aryl groups such as phenyl, tolyl, xylyl, naphthyl; aralkyl groups such as benzyl, phenylethyl, methylbenzyl, naphthylbenzyl; vinyl, allyl, oleyl, etc. Examples of alkenyl groups include cycloalkenyl groups such as cyclopentadienyl and 2-cyclobutenyl, and alkenylaryl groups such as vinylphenyl. Among them, lower alkyl groups having 1 to 6 carbon atoms are effective in removing paint dust.

In the formula, R' is not only hydrogen, but also methyl, ethyl,
C4 to C2 alkyl groups and aryl groups such as propyl, butyl, amyl, hexyl and octyl; C1 to C6 acyl groups such as acetyl, propionyl and butyryl; nioxime residues; and the like.

The above-mentioned organopolysiloxane resin used in the present invention can be used without any restriction on molecular weight as long as it can be dispersed and/or dissolved in water and organic solvents as described above, but commonly used organopolysiloxane resins can be used. is a number average molecular weight of approximately 3
00 to about 1.000.000, preferably about 1,000 to about 500.000. The organopolysiloxane resin preferably has a reactive group such as a hydroxyl group or an alkoxy group in its molecule. Examples of such organopolysiloxane resins include,
Z-6018, Z-6188, 5ylkyd 50, D
C-3037 (Dow Corning product), KR
-216, KR-218, KSP-1 (Shin-Etsu Silicone product), TSR-160, 7SR-165 (Tokyo Shibaura Electric product), 5E1821.5E1980.5E91
40,5RX2n. PRX305.5H237,5H9
Examples include 551RTV (Toshi siliconin product).

A typical curing mechanism of organopolysiloxane resin is a reaction between silanols or silanol and 〉5i-OR',
) Condensation reactions such as the reaction between silanols produced by hydrolysis of Si-OR' or the reaction between the generated silanol and) Si-OR'; and Addition reactions such as the reaction between () S 1-CH=CH2 and H5i. It is carried out by a polymerization reaction (R' used above has the same meaning as above).

In the present invention, the use of a resin composition containing an alkali metal compound in the above-mentioned luganoborisiloxane resin has the advantage that a film from which paint dust can be easily peeled off can be obtained.

The above alkali metal is MaeX'E' (M in the formula
represents an alkali metal selected from Li, Na and K, and X represents an inorganic acid group, a hydroxyl group or an organic acid group. Moreover, a is an integer of 1-4. ) can be used.

Inorganic acid radical refers to the remaining portion of an inorganic acid molecule after removing one or more hydrogen atoms that can be substituted with a metal.
, C1θ, Bre and Ie (7)) and N
Os e, (,Q,tePO4”e,HPO42e,S
O4”e, HSO4”eMnO4e, Craft”
S i Oa4eSiOm29. BOte, VO4
It can include atomic groups such as "e, w04"el'.

In addition, the term "organic acid radical" refers to the remaining portion of a saturated or unsaturated monocarboxylic acid or polycarboxylic acid molecule after removing one or more hydrogen atoms that can be substituted with a metal, such as HCOO"' and the general formula The saturated monocarboxylic acid group represented by the general formula eOOC (
CH-h, QOOe (n: O~10) Saturated dicarboxylic acid group represented by Te; Unsaturated acid group such as maleic acid, oleic acid, linoleic acid: Polyvalent carboxylic acid group such as tartaric acid, citric acid, pyromellitic acid, trimellitic acid, etc. Examples include acid roots.

Therefore, the following can be exemplified as representative examples of the alkali metal compounds represented by the above formula.

LiF, LiC1, LiBr, LiI, Na
F, NaCl, NaBr, NaI, KF, KCl, KB
r, KI, LiNOs, NaNOs, KNOs,
L i * COs, Nag Co.

K m N On, L im P 04, N a
s P OaKPO,, L l * S O4, Na
g *SO4 to S04; LiMn0n, N
a M n O4K M n O4, LizCraOy
, Na z Cr tK2CrxOt, L i 4 S
104, Li *SiN a 4 S iOa, N
a * S i O s , K a S ioK R
S i Os, L i B O2, NaBO,, KBO
,, L i s V O-, N a V 04 ,
KSVO4, Li*WOn, NaaWO4, K,
WO2: HCOOLi, HCOONa, H
COOK, Lizc*oa, N a 2 C* 04
, KaCaO4, CHs COOL l, C
Hs COON a, CH=COOK, C=H
=COOLi, L 100 C-CHz -COOL
i, lithium citrate, sodium citrate, potassium citrate, lithium tartrate, lithium trimellitate,
Lithium pyromellitate etc.

Among these alkali metal compounds, chlorides have the greatest ability to remove paint dust. However, when using such strong acid salts, they have the property of causing rust on metal materials, so care must be taken when using them.Secondly, carbonates, silicates, and Acetate salts are preferred because they have a long-lasting paint dust removal effect and do not cause a large amount of flaking. Further, among these alkali metal compounds, lithium compounds are preferred because they have a greater paint dust removal effect than other sodium compounds and potassium compounds.

These alkali metal compounds can be used alone or in combination of two or more, and the blending amount is 0.2 to 30% by weight, preferably 0.5% by weight in total with the organopolysiloxane resin. ~10% by weight. If the amount of the alkali metal compound is less than 0.2% by weight, the paint dust removal effect will be reduced, and if it exceeds 30% by weight, the physical properties of the film will deteriorate and it will not be able to withstand long-term use. It is desirable to use it within this range.

In addition, the coating formed from the composition of the present invention has an adhesion force of 100 g/cm with paint dust as measured by the following method.
Hereinafter, it is preferably in the range of 1 to 50 g/c.

Using a test board with approximately 30 pages or more of paint dust on it, place the adhesive surface of the adhesive force measurement attachment (width: 4 x 4 cm) on the surface of the paint dust using a two-component adhesive. After bonding and fixing with a synthetic poxy resin adhesive, the test plate was fixed at 20°C and the above attachment was pulled at a speed of 50 mm/min using a Schopper tensile tester to ensure that the paint dust was coated. The adhesion force was defined as the minimum force required to separate the adhesive from the adhesive.

The resin composition of the present invention is obtained by dissolving or dispersing the polyorganosiloxane resin in an organic solvent. As the organic solvent, chain or bulk hydrocarbons, ketones, esters, alcohols, water, etc. can be used. In addition, when using an alkali metal compound, a mixture of an alkali metal compound mixed with an organic liquid obtained by dividing or dissolving an organopolysiloxane resin in an organic solvent may be prepared using a steel ball mill.
Dispersion using a conventional dispersion method such as a pebble mill or attritor can be preferably used.

Pigments, various additives, and the like can be added to the resin composition of the present invention as required.

The resin composition of the present invention has a solid content of about 15 to 70% by weight, preferably 25 to 45% by weight, and is applied by spray coating, spacing, dipping, electrostatic coating, flow coating, etc. Although the coating film thickness is not particularly limited, it is preferably 5 parts or more, especially 10 parts based on the dry coating film.
The drying temperature of the coating film, which is preferably in the range of ~50F, can be arbitrarily selected depending on the composition, and may be forced drying at room temperature or 100°C or lower, or heated and dried at 100°C or higher.

The resin composition of the present invention can be applied to metals, plastics, glass, wood, inorganic materials, rubber, previously painted surfaces, and the like.

Hereinafter, the present invention will be explained in more detail with reference to Examples. Parts and percentages are by weight unless otherwise specified.

Example 1 SE-1821 (manufactured by Toshi Siliconin Company, trade name, addition polymerized organopolysiloxane resin, solid content 40%) 1
A mixture of 00 parts and 10 parts of 5E-1B21Cat (manufactured by Toshi Siliconin Corporation, trade name, platinum-based catalyst) was applied to a steel plate so that the dry film thickness was approximately 50 pm, and the mixture was dried at room temperature for 10 hours to harden. A coating was obtained.

Example 2 10 pieces of the same silicone 5E-1821 as in Example 1
After dispersing 0 parts and 2 parts of lithium acetate in a paint conditioner, the same S E-1821 as in Example 1 was prepared.
A mixture containing 10 parts of Cat was applied and dried in the same manner as in Example 1 to obtain a cured film.

Example 3 100 parts of PRX-305 (manufactured by Toshi Siliconin ■, trade name, condensed organopolysiloxane resin, solid content 40%, number average molecular weight 300,000) and 1 part of lithium citrate were added in the same manner as in Example 2. A cured film was obtained by dispersing, coating and drying.

Comparative Example 1 Bisilon LID460M (manufactured by Bayer AG, trade name, silicone polyester resin) was applied to a steel plate with a dry film thickness of 50F.
It is applied and dried so that it looks like this.

Comparative Example 2 100 parts of Bisilon UD460M and 5H2 on steel plate
A mixture of 1 part of 00 (manufactured by Toshi Siliconin ■, trade name, silicone oil) was applied to a dry film thickness of 50F and dried.

Examples and comparative examples are summarized in Table-1.

Table 1 *1 Paint dust: Epoxy paint (Epomarin Intermediate Paint White, manufactured by Kansai Paint Company, trade name), acrylic paint (Rethane PG-80 White,
Manufactured by Kansai Paint (trade name), polyester paint (
Retan No., 2000 points, manufactured by Kansai Paint Company,
After spray painting the paint (trade name) until the dust was falling and the dust film thickness was about 3+am or more, it was dried at room temperature for 24 hours and the peelability 02 and adhesion strength were measured.

*2 Peelability: Peeling workability was evaluated when the coating was peeled off using paint dust. 0 (can be removed by simply rubbing lightly), 0 (can be removed by simply rubbing with a little force).

), @ (It will peel off if you apply force and rub it.), Δ
(It will not come off unless you rub it with a lot of force.), ×(
Cohesive failure of paint dust. ) *3 A repellency test was conducted by putting the dust attached to the resistant coating into the original paint. 0 (no repelling is observed at all), ○(
A slight flicker is observed. ), Q (repelling is observed), △ (many repelling is observed), X (remarkable repelling is observed) *4 Paint dust falls on the coated plates obtained in the durability examples and comparative examples. Spray paint, dry at room temperature for 24 hours, remove the paint dust, then spray paint so that the same type of paint dust falls on the peeled painted board, dry at room temperature for 24 hours, then remove the paint dust. do the
This coating and dust removal were repeated to determine the number of times it became difficult to remove the dust.

[Effects of the Invention] Rust can be prevented by coating metal substrates such as hangers and paint booths with the resin composition of the present invention.

If the resin composition of the present invention is applied to hangers, paint booths, etc. before the painting process, paint dust that has been applied to hangers, paint booth walls, etc. during the painting process can be easily removed by simply pulling it off with your hands. Can be peeled off and removed. Furthermore, since it has good durability, paint dust can be removed repeatedly.

Claims (1)

[Claims] (1) Unit formula R_nSi(OR')_mO_(_4_-
_n_-_m_)_/_2 [In the formula, R represents a monovalent organic group bonded to silicon through a carbon-silicon bond or a hydrogen atom, R' is a hydrogen atom, an alkyl group, an acyl group, an aryl group of C_1_-_2_0 Indicates a group or oxime residue. However, n and m are each less than 4, and n+m is 4.
less than ] A resin composition for removing paint dust, which contains an organopolysiloxane resin represented by the following as a main resin component.