WO2006076449A1

WO2006076449A1 - Abrasive composition

Info

Publication number: WO2006076449A1
Application number: PCT/US2006/001011
Authority: WO
Inventors: Shigeaki Dohgoshi
Original assignee: 3M Innovative Properties Co
Current assignee: 3M Innovative Properties Co
Priority date: 2005-01-14
Filing date: 2006-01-12
Publication date: 2006-07-20
Anticipated expiration: 2007-07-14
Also published as: CA2594786A1; JP2006193658A; EP1841832A1; CN101098944A; JP2008527149A

Abstract

[Problem to be solved] To provide an abrasive composition that is excellent in abrasive power, and capable of erasing abrasive traces formed on a coated film in a short period. [Means for solving] An abrasive composition which comprises at least water, abrasive particles, a petroleum-based solvent, a surfactant, and a thickener, further comprises 0.1 to 20% by weight of a plasticizer.

Description

Abrasive Composition

Field of the Invention [0001]

The present invention relates to an abrasive composition, and particularly relates to an abrasive composition suitable for buff abrading a coated film surface of an automobile. Background [0002]

An external plate part of a car such as a bonnet and a door that has been damaged from a car accident, etc. may be repaired in a manner which is described in patent document 1. First, a dented portion due to damage is hammered out, a putty is applied on the surface, a primer surfacer is sprayed thereto, to make the surface flat. [0003]

Then, an undercoating and an overcoating paints are sprayed thereto with a spray gun. Dusts and dirt are thereafter removed by using very fine water-resistant abrasive paper, texture- adjusting is carried out through water-resistant abrasive paper or buff abrading with fine compound, and further polishing is carried out by using a super-fine/ultra-fine particle compound so as to finally apply luster. [0004]

At present, since an overcoating paint is atomized by a spray gun, and sprayed onto a surface to be coated, convex- concave inevitably is generated on the coated film surface after the paint has been dried and set. This is because, when the atomized paint particles are again joined to other particles on the coated film surface, they form various shapes depending on the following various conditions: viscosity, surface tension and fluidity of the paint, evaporating rate of the solvent and diameter of the spray gun, pressure and flow rate of the air, flow rate of the paint, distance to a surface to be coated, spraying angle, temperature and humidity at the time of operation, etc. The convex-concave on a coated film surface is generally referred to as "orange peel". [0005] In the repair process, orange peel state of a newly repaired portion need to be coincident in pitch and height of convex-concave with the original orange peel on the coated film surface; however, they are usually different as the above-mentioned conditions vary. In order to make them coincident with each other, the repaired portion is abraded with water-resistant abrasive paper, a compound and the like so as to approximate with a circumference portion. This process is referred to as texture matching. [0006]

In the case when an orange peel is rougher than that on the circumference portion, the texture matching is generally carried out by abrading convex parts with water-resistant abrasive paper of #1000 (PlOOO) to #3000 (P3000) so as to make pitch and height of convex-concave on the coated film surface coincident with a circumference portion. Thereafter, buff abrading with a fine compound is conducted so as to remove abrasive traces of the water-resistant abrasive paper, and then texture matching is conducted through buff abrading with a super-fine compound so as to remove buffing traces of the fine compound. Finally, a finishing process is carried out by using ultra-fine compound so as to provide luster. [0007]

Coating and repairing dealers rarely have a coating booth equipped with a perfect air cleaner, so when coating is conducted under a simple booth or no booth, very fine trashes or dusts in the air stick and absorb paints to make heap or roughness. Removing this with water-resistant abrasive paper leaves abrasive traces thereon. Further, water-resistant abrasive paper is not able to remove roughness on a convex portion. So the abrasive traces or the roughness have to be erased combined with matched in texture, with using a compound. [0008]

In buff abrading, an electric or air driving polisher having a rotation of about 1500 to 3000 rpm is used, and a towel buff, a wool buff, a corduroy buff, a sponge buff and the like are used for a surface to be contact with a coated film surface. The liquid compound is dropped on the contact surface of the buff, and a coated film surface is buff-abraded. [0009]

A conventional compound employed for a buff abrading process contains abrasive particles, and oils and fats dissolved in a petroleum solvent, which are emulsified or dispersed in water with a surfactant. For example, patent document 2 describes an aqueous abrasive composition which comprises a lubricating oil such as dibasic acid esters and phosphoric acid esters. Patent document 3 describes an aqueous abrasive composition which comprises plastic particles. [0010]

Water-proof abrasive paper of #2000 presently has the finest pitch, but forms abrasive traces. So the abrasive traces have to be abraded out with a buff and a compound, but the operation takes labor and time since poor abrasive efficiency due to free particles. Although abrasive cloth-paper provides high abrasive efficiency, abrasive traces becomes rough. In addition, abrasive cloth-paper abrades only a convex portion of an orange peel, and does not abrade a concave portion.

[Patent document l] Japanese Patent Kokai Publication No. 123065/1997

[Patent document 2] Japanese Patent Kokai Publication No. 2004- 25323

[Patent document 3] Japanese Patent Kokai Publication No. 2004- 89907

Disclosure of the Invention Problems to be solved by invention [0011]

The present invention solves the above-described conventional problems and the object thereof is to provide an abrasive composition that is excellent in abrasive power, and capable of erasing abrasive traces formed on a coated film in a short period. Means for solving problems [0012]

The present invention provides an abrasive composition which comprises at least water, abrasive particles, a petroleum -based solvent, a surfactant, and a thickener, further comprises 0.1 to 20% by weight of a plasticizer, and the object is achieved thereby. Effect of invention [0013]

An abrasive composition of the present invention is unlikely to disorder convex-concave of an orange peel as being liquid, excellent in abrasive power to be able to erase abrasive traces formed on a coated film in a short period, and a surface after being abraded has excellent smoothness. Detailed Description of Embodiments [0014]

An abrasive composition of the present invention is a water-based composition comprising at least water, abrasive particles, a petroleuπr based solvent, a surfactant, a thickener and a plasticizer. [0015] Plasticizer

A plasticizer is preferably excellent in swelling and lubricating properties for a coated film. This is because a surface of the coated film is softened to improve abrasive power. The plasticizer is found to have a solubility parameter (SP value) of 8.7 to 11, preferably 9 to 10. [0016]

The solubility parameter ( δ i) referred herein is the value calculated from the Small equation. A calculation method is shown on VII/682 to VII/685 of Polymer Handbook Forth Edition. [0017]

Examples of preferred plasticizers include acetyltri-n-butyl citrate, acetyltriethyl citrate, triethyl citrate, tributoxy phosphate, dimethyl glutarate, a mixture of dimethyl glutarate, dimethyl adipate and dimethyl succinate, and the like. Particularly preferred plasticizers include acetyltri- n-butyl citrate. [0018]

A plasticizer is contained such that the plasticizer concentration of an abrasive composition is from 0.1 to 20% by weight, preferably from 0.5 to 5% by weight. When the plasticizer concentration in an abrasive composition is less than 0.1% by weight, abrasive efficiency is not sufficiently improved; the concentration exceeding 20% by weight may cause deterioration of the coated film.

[0019]

Abrasive particles Abrasive particles to be used in the present invention preferably have an average particle diameter ranging from 0.5 to 50 μ m. In particular, the average particle diameter is preferably from 10 to 50 μ m in a roughly abrading step of buff abrasion and is preferably from about 0.5 to about 10 μ m in a finishing abrading step. When the average particle diameter of abrasive particles is below 0.5 μ m, abrasive power is too weak; if the average particle diameter exceeds 50 μ m, abrasive scratches become too deep, thereby consuming much time for abrading. Hardness of an abrasive material constituting abrasive particles that is used approximately ranges from 3 to 10 in the old Mohs hardness, preferably ranges from 4 to 10. For the old Mohs hardness being less than 3, abrasive power is too weak. Examples of the abrasives include well known natural abrasives and artificial abrasives.

[0020]

Natural abrasives that are suitably used include (sintered) diatomaceous earth, tripoli, (sintered) kaolin, silica powder, and the like; artificial abrasives that are suitably used include alumina abrasives (e.g., a sintered alumina abrasive, a brown alumina abrasive/a white alumina abrasive/a pink alumina abrasive/mono-crystalline fused alumina abrasive, and the like), colloidal silica, synthetic silica, calcium carbonate, stannic oxide, and the like. In the present invention, these abrasives can be used alone or in combination of not less than two kinds. [0021]

The content of abrasive particles that may be used ranges from 1 to 60% by weight based on 100% by weight of the total abrasive composition. When the content of abrasive particles is less than 1% by weight, abrasive power is too weak; when the content exceeds 60% by weight, finishing is poor and powder scattering in operation is increased. [0022] Petroleum-based solvent

A petroleum -based solvent stands for an organic solvent obtained by fractional distillation of petroleum. Petroleum-based solvents used in the present invention favorably comprise saturated aliphatic hydrocarbons and/or saturated aliphatic cyclic hydrocarbons, having a boiling point of 120⁰C or more, which improve wetness of an abrasive composition for a coated film in order to improve abrasive power of abrasive particles, or possess action such as slightly softening a coated film. When the boiling point of a petroleum-based solvent is below 12O⁰C, the action of the petroleum -based solvent and the stability of the emulsion cannot be sufficiently obtained on account of too quick drying. [0023] Examples of such petroleum-based solvent include petroleum -based aliphatic solvents such as kerosine, solvent naphtha, Stoddard solvent; saturated aliphatic hydrocarbons such as nonane, decane and dodecane! terpene -based solvents such as camphor oil, turpentine oil and pine oil; terpenes such as pinene and dipineneJ and the like. These can be used alone or in combination of not less than two kinds. [0024]

Aromatic hydrocarbons have an aromatic ring and thus is harmful to a human body, and also odor thereof is strong as well, thereby having a detrimental effect on the environment. Accordingly, no use of aromatic hydrocarbons is preferable. [0025]

A petroleum-based solvent is used in an amount so as to account for

10 to 60% by weight, preferably account for 20 to 40% by weight of an abrasive composition. When content of petroleum-based solvent is below

10% by weight, an abrasive composition dries too quickly to have sufficient abrasive amount. When it exceeds 60% by weight, an abrasive composition slowly dries and remains thick for long time, so it is difficult to notice stop timing for the operations.

[0026]

Surfactant A surfactant decreases interfacial tension between a dispersion phase and a dispersion medium thereof and is a component necessary for dispersing abrasive particles, emulsifying a solvent, or the like. Examples of the surfactants include soaps made of fatty acids such as oleic acid and stearic acid, polyoxyethylene alkyl ether, and the like. [0027] Thickener

For increasing and controlling viscosity of an abrasive composition, a thickener can be added. Extraordinary low viscosity of an abrasive composition tends to cause the composition to flow down a vertical surface of an automobile, and therefore a workman cannot suitably abrade the automobile using the composition. Hence, a thickener is used for adjusting the viscosity of an abrasive composition.

[0028]

Typical examples of the thickener include hydrated aluminum silicate, a dimethyldioctadecyl salt of montmorillonite clay, alkali- soluble acrylic polymer emulsion, colloidal silica, and heavy metal soaps such as lead oleate, zinc oleate, zinc stearate and aluminum stearate. Preferred thickeners to be used in the present invention include an aqueous emulsion of alkali-soluble acrylic polymer. [0029]

Furthermore, a thixotropic agent can be used. A thixotropic agent is a colloidal solution, and when an outer force is applied thereto, the solution changes from gel to sol to exhibit fluidity. When the sol is allowed to stand, it returns to the original gel again. Examples of the thixotropic agent include inorganic substances such as anhydrous aluminum silicate, clay and fine mica powder, and organic substances such as fatty acid derivatives and hydrogenated castor oil.

[0030]

Other additives For the purpose of inhibition of growth of bacteria in an abrasive composition, a stabilizer and a preservative can be employed. Typical examples include methylparaben, ethylparaben, propylparaben, butylparaben, potassium sorbate, sorbic acid and o-phenylphenol. A pigment, a dye and a flavor can also optionally be added to an abrasive composition of the present invention. [0031]

Preparation of abrasive composition

Blending the above-described components with water can give a abrasive composition of the present invention. Examples of water that may be used include tap water, distilled water, and deionized water. Deionized water is preferable. This is because ions or other substances are removed therefrom that facilitate growth of microorganisms in an abrasive composition, thereby to cause a low possibility of growing the microorganisms. Water is used in an amount so as to account for 10 to 60% by weight, preferably 20 to 40% by weight of an abrasive composition. [0032]

When an abrasive composition is prepared, for instance, a mixture is continuously stirred while adding to water the components such as a surfactant, a thickener, a plasticizer, an additive, a petroleum -based solvent and abrasive particles. Thereafter, the abrasive composition is mixed using a high shear blender until a uniform dispersion is formed. [0033] Process of finishing coated film surface

According to a process of finishing a coated film surface of the present invention, by first, dusts, coating lumps, coating defects and the like on a surface of a coated film which has been coated with spraying, is removed by using a water-resistant abrasive paper having an abrasive particle size of 5 to 15 μ m (#1000 to #3000 according to JIS R 6001) and water.

[0034]

Abrasive traces generated by a water-resistant abrasive paper, an elastic abrasive material and the like, are then erased by using an abrasive composition of the present invention. Specifically, an abrasive composition of the present invention is placed on a hard-type buff such as an wool buff, and a coated film surface, on which abrasive traces have been formed, is abraded therewith. Tools for abrading that may be used include a single action sander, a single polisher, and the like which are equipped with a hard-type intermediate buff pad.

[0035]

Then, polishing is conducted for finish by using a sponge buff and a liquid abrasive composition having an abrasive particle size of about 2 to 3 β m.

[0036]

A plasticizer generally is poor in volatility, so the plasticizer remained in coated film organization may have bad influence on the physical properties of the coated film after being repaired. Therefore, when abrasive traces are erased with an abrasive composition of the present invention, a coated film which have contacted with a plasticizer is preferred to be removed entirely by further conducting polishing as described above.

[0037]

The following examples further illustrate the present invention, however, these are not to be construed as limiting the present invention to their details. [Examples] [0038] Example 1

Ion exchanged water and a surfactant were weighed and then the resulting solution was uniformly stirred. To this mixture were added abrasive particles and then was stirred until a uniform dispersion was obtained. A petroleum-based solvent and remaining components were added to this while stirring speed was gradually increased to be a uniform emulsion to obtain an abrasive composition. The composition of this abrasive composition is shown in Table 1. The concentration of the plasticizer is 0.99% by weight. [0039] [Table 1]

a: Acetyltri-n-butyl citrate (SP Value'- 9.06) b^: Alumina having an average particle diameter of 20 μ m [0040]

The resulting abrasive composition was evaluated in abrasive power and finishing abilities. The evaluation procedures are as follows.

1. Abrasive power To a bonde steel plate of 600 mm x 450 mm and 0.8 mm thick was applied a black paint "SUPERIO 480" manufactured by Nippon Paint K.K. with a spray gun so that a dry coated film was formed to 20 to 30 μ m thickness. After the coated film was dried overnight, "SUPERIO 240 CLEAR" manufactured by Nippon Paint K.K. was spray coated thereon so that a dry coated film was formed to 20 to 40 μ m thickness, and then the resultant was cured in an oven at 6O⁰C for 1 hour to obtain a test piece. [0041]

5 g of the abrasive composition was put on a coated film surface of the test piece, and the test piece was then abraded at a speed of 1500 rotations per minute for 50 seconds by using an electric single polisher manufactured by Hitachi K.K. The buff used at this time is a separate wool buff manufactured by 3M Company "SEPARATE WOOL BUFF 5760", which was connected to the polisher via "SEPARATE BUFF CUSHION PAD 5743" and "TAPERED BUFF PAD 5718". [0042]

Weight change of the test piece before and after abrasion was measured to determine an abrasive amount of the coated film. The results are shown in Table 4. [0043] 2. Finishing ability 1

"SCALLOP DISK #1200" manufactured by 3M Company was applied to "SCALLOP PAD", and they were made to go and back on a coated film surface of the test piece 30 times by hand to form abrasive traces. [0044]

3 g of the abrasive composition was put on the coated film surface of the test piece, and then the test piece was abraded at a speed of 1500 rotations per minute for 10 times go and back by using an electric single polisher manufactured by Hitachi K.K. to erase the abrasive traces. The buff used at this time is "SEPARATE WOOL BUFF 5760" manufactured by 3M Company, which was connected to the polisher via "SEPARATE BUFF CUSHION PAD 5743". [0045]

A face element was exchanged to "SEPARATE SOFT SPONGE BUFF 5764" manufactured by 3M Company, an ultrafine particle compound manufactured by 3M Company "HARD 2L" was placed on the coated film surface, and polishing was conducted. [0046]

Surface roughness (Ra) of the coated film surface after being polished was measured with "SURFCORDER SE 1700 a " manufactured by Kosaka Kenkyusho K.K. The measurement was repeated five times, and took an average as the evaluation value. [0047]

3. Finishing ability 2

"401Q WATER ABRASIVE SHEET" #1500 manufactured by 3M Company was placed on a coated film surface of the test piece with a 4 kg weight, and they were made to go and back 20 times to form abrasive traces. [0048] 3 g of the abrasive composition was put on the coated film surface of the test piece, and then the test piece was abraded at a speed of 1500 rotations per minute for 10 times go and back by using an electric single polisher manufactured by Hitachi K.K. to erase the abrasive traces. The buff used at this time is "SEPARATE WOOL BUFF 5760" manufactured by

3M Company, which was connected to the polisher via "SEPARATE BUFF

CUSHION PAD 5743".

[0049]

A face element was exchanged to "SEPARATE SOFT SPONGE BUFF 5764" manufactured by 3M Company, an ultra-fine particle compound manufactured by 3M Company "HARD 2L" was placed on the coated film surface, and polishing was conducted.

[0050]

Surface roughness (Ra) of the coated film surface after being polished was measured with a laser microscope "VK-9500" manufactured by Keyence

K.K. The measurement was repeated five times, and took an average as the evaluation value.

[0051]

Example 2 An abrasive composition was prepared according to substantially the same manner as described in Example 1 except that content of the plasticizer was 4.76% by weight. Composition of this abrasive composition is shown in Table 2. [0052] [Table 2]

a: Acetyltri-n-butyl citrate (SP Value: 9.06) b'- Alumina having an average particle diameter of 20 μ m [0053]

The resulting abrasive composition was evaluated in abrasive power according to substantially the same manner as described in Example 1. The results are shown in Table 4. [0054] Examples 3 to 6

Abrasive compositions were prepared according to substantially the same manner as described in Example 1 except that plasticizers as shown in table 5 were employed. The resulting abrasive compositions were evaluated in finishing ability according to substantially the same manner as described in Example 1. The results are shown in Table 5. [0055]

Comparative Example

An abrasive composition was prepared according to substantially the same manner as described in Example 1 except that no plasticizer was employed. The composition of this abrasive composition is shown in Table 3. [0056] [Table 3]

^b Alumina having an average particle diameter of 20 μ m [0057] The resulting abrasive compositions were evaluated in abrasive power and finishing ability according to substantially the same manner as described in Example 1. The results are shown in Tables 4 and 5. [0058]

[Table 4]

Evaluation results of abrasive power

[0059]

The results of Table 4 show that abrasive compositions of the Examples are excellent in abrasive power as compared with that of Comparative Example. [0060] [Table 5] Evaluation results of finishing ability

Ά- Acetyltri-n-butyl citrate ("CITROFLEX A- 4" manufactured by

Morimura Shoji KK.) b: Glyceryl triacetate ("TRIACETINE" manufactured by Daihachi

Kagaku K.K.) c: Dioctyl adipate ("SANSOSIZER DOZ" manufactured by Shin Nippon

Rika KK.) d^ Diisononyl adipate ("DINA" manufactured by Daihachi Kagaku K.K.) e^ Tricresyl phosphate ("TCP" manufactured by Daihachi Kagaku K.K.) [0061]

The results of Table 5 show that a surface finished by erasing abrasive traces with the abrasive compositions of Examples, has excellent smoothness as compared with that of Comparative Example.

Claims

Claims Claim 1

An abrasive composition which comprises at least water, abrasive particles, a petroleum -based solvent, a surfactant, and a thickener, further comprises 0.1 to 20% by weight of a plasticizer. Claim 2

The abrasive composition according to claim 1, wherein the plasticizer has a solubility parameter of from 8.7 to 11. Claim 3 The abrasive composition according to any one of claim 1 or 2, wherein the plasticizer is at least one selected from the group consisting of acetyltri-n-butyl citrate, acetyltriethyl citrate, triethyl citrate, tributoxy phosphate, dimethyl glutarate, and a mixture of dimethyl glutarate, dimethyl adipate and dimethyl succinate. Claim 4

The abrasive composition according to any one of claims 1 to 3, wherein the abrasive particles have an average particle diameter of from 2 to 30 μ m.