JPS6055065A - Antistatic clear paint - Google Patents

Abstract

PURPOSE:To provide a paint which gives a coating film having excellent transparency, mar resistance and antistatic performance, by mixing an electrically conductive powder mainly composed of tin oxide with a paint binder composed of a specified copolymer mainly composed of methyl methacrylate. CONSTITUTION:A copolymer composed of 70-98mol% of methyl methacrylate monomer and 25-2mol% of a monomer of formula I or II (wherein R1 is H, CH3; n is 1-10; m is 3-9), such as hydroxyethyl acrylate or triethylene glycol monoacrylate, is used as a paint binder. 70-350pts.wt. electrically conductive powder having a particle size of 0.2mum or below and mainly composed of tin oxide is mixed with 100pts.wt. binder to obtain the desired antistatic clear paint. This paint is suitable for use in coating semiconductor wafer conservation containers.

Description

[Detailed Description of the Invention] Technical field: The present invention provides antistatic coating 11: coating*;1. In particular, the present invention relates to a paint that has antistatic properties and transparency, and forms a coating film that has superior hardness and strength.

Prior art: Semiconductor wafer storage containers, VV containers, Ichiiso parts, materials and wall materials for semiconductor manufacturing factories, etc. Depending on the application, it is necessary to have an antistatic effect.

To this end, these members have conventionally been coated with paint containing carbon powder or metal powder, or formed by kneading carbon powder, carbon fiber, gold@fiber, etc. into resin. However, in these conventional methods, the coating film and molded article themselves are colored and are therefore opaque, making it impossible to see through the contents. Therefore, it is not possible to use a window as a part that requires the band "EM Bh" to be fastened.

Japanese Unexamined Patent Publication No. 57-85866 discloses a paint that is transparent and has a function of preventing staining. This paint is mainly composed of tin oxide containing antimony and has a particle size of 0.
．． A paint binder contains conductive fine powder of 2 μm or less. The key to this paint is to disperse the conductive fine powder to the full height.
It is important to stably express T-blocking function.

Object of the invention: An object of the invention is to provide a coating material with excellent transparency and antistatic effect. It is an object of the present invention to provide a coating material that can form a coating film that has excellent scratch resistance and maintains antistatic effect and transparency for a long period of time. A further object of the present invention is to provide a fully formed 1r:f paint that has excellent hardness and strength.

Summary of the invention: The present invention provides that a paint binder obtained by mixing a small amount of a hydroxyl group-containing heptamine into a methyl methacrylate monomer completely prevents the re-aggregation of fine metal powder and exhibits outstanding dispersion ability; Moreover, the present invention was completed based on the inventor's knowledge that the resulting coating film has excellent transparency and antistatic function, is high in hardness, and has scratch resistance. Therefore 1 unexploded CHsO) m-11 (but lt,
is a paint binder consisting of a copolymer containing 2 to 25 moles of semi-m isomers represented by 1 mosukeke-C11, groups i n-1 to 10 + and m-3 to 9); Contains conductive powder with a particle size of 0.2ttm or less.
The conductive powder is contained in a ratio of 70 to 350 parts by weight per 100 parts by weight of the paint binder, thereby achieving the above object.

The coating film formed by the paint of the present invention is high (i'J4
+, +: with c12. And excellent f1. Drunk I! %;1. %
In order to demonstrate the vulnerability.

It is necessary that the paint binder contains 70 to 98 moles of the methyl methacrylate monomer in the paint binder. In order for the above-mentioned coating N to have excellent transparency, anti-static and anti-electrostatic functions, it is necessary to add 2 to 25 moles of paint to the paint binder.

Preferably, the content should be in the range of 3 to 15 moles. If the content of the hexamer having an acid group in / is less than 2 moles, the metal fine powder cannot be sufficiently dispersed, and therefore the resulting coating film has poor transparency.

When it exceeds 25 moles.

The resulting coating film has poor water resistance and cannot withstand long-term use.

The monomers having the above hydroxyl group have the general formula CH, - example, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyoctyl (meth)acrylate, hydroxy 2-ethylhexyl (meth)acrylate. and so on.

The monomers used are polyethylene glycol mono(meth)acrylates, including, for example, triethylene glycol mono(meth)acrylate I/-), tetraethylene glycol mono(meth)acrylate.

pentaethylene glycol mono(meth)acrylate,
hexaethylene glycol mono(meth)acrylate,
There are heptaethyl 1/nglycol mo/(meth)acrylate and octaethyl 1/nglycol 7(meth)acrylate.

The paint binder copolymer containing the above methyl methacrylate monomer and the above hydroxyl group-containing monomer can be prepared by nine conventional polymerization methods, such as the IN# method, the bulk method, the bulk method, and the emulsion polymerization method. In order to ensure the transparency of the paint film, it is necessary to use a particle size of the conductive powder containing tin oxide as the main component (1.2 lim) based on the amount of Ha.
It is contained in a proportion of ~350 parts by weight, preferably 100 to 300 parts by weight. If the fine powder is less than 70% by weight, even if the degree of dispersion is sufficient, the coating film obtained will not exhibit sufficient conductivity, and therefore the antistatic effect, which is one of the objects of the present invention, will not be exhibited. 350 views 1, 11
If it increases by 1, it becomes overcrowded and the dispersion of the fine powder deteriorates, resulting in poor dispersion of the fine powder.

The transparency of the resulting coating film was 11%.

The paint of the present invention is prepared by dissolving the paint binder (-) in an organic solvent and then mixing it with a tetraelectric fine powder containing tin oxide as the main component. Examples of equipment commonly used for dispersing and compounding paints include sand mills, ball mills, and high-speed [+2
A one-turn stirrer, three rolls, etc. may be used. In order to further enhance the dispersion of this fine powder, dispersion aids such as silane coupling agents, surfactants, oleic acid, and lecithin may also be used.

The antistatic transparent coating of the present invention thus prepared is applied to an object to be coated by a general coating method such as a spray method, a bar code method, a doctor blade method, or a dipping method.

Transparency of the coating film obtained by applying it to the target object? To further improve the quality, it is recommended to apply a puff finish to the paint film.

Temporary seal! : A preferred embodiment of the present invention will be explained below.

Example 1 ~ (~ Synthesis of binder resin: 250 g of toluene was placed in a separable flask equipped with a cooling tube, a stirrer, and a dropping funnel.
I prepared g. This was heated under a nitrogen gas stream to the boiling point of toluene, 110C. =Il+], 112.5 g of methyl methacrylate, 1-12.5 g of β-hydroxyethyl methacrylate, and 1. A mixed solution of 0.5 g of azobisisobutyronitrile as a polymerization initiator was prepared, and this was charged into a dropping funnel. The temperature of toluene in the flask is 1
When the temperature reached 10° C., a mixture of monomer and polymerization initiator was added dropwise from the dropping funnel over a total of 2 hours to polymerize.

Then, the temperature inside the flask was set to 90°C. Next, 2 g of azobisisobutyronitrile was dissolved in 20 g of K1-7 in a dropping funnel, and N1 was added to ff1-.
The mixture was added dropwise into the syringe flask over 2 hours. After completion of the dropwise addition, polymerization was further continued at 90° C. for 2 hours. The polymerization average molecular weight fd of the obtained copolymer was 45,000. The polymerization rate is 9
It was 9chi.

B) Preparation of paint: Bingu solution 100 synthesized in Section B
g, 160 g of toluene and particle size (1,1/1 m t
63.2 g of 7J antimony-containing tin oxide powder was placed in a ball mill. Disperse this for 48 hours and apply the desired paint.
I got an answer.

(q) Preparation of coating film and performance evaluation: The above coating was applied to a thickness of 3 μm on a transparent vinyl chloride plate, and the solvent was dried. The measurement results of the surface resistivity, total light transmittance, haze value, and pencil hardness of the resulting coating film are shown in Table 1.The surface resistivity is A.
STM D257. Total light transmittance and haze value are ASTM
T)1003. And the pencil hardness is JISK-5400
It was measured by a test method based on

Comparative Example 1 A monomer of polymethyl methacrylate was synthesized in the same manner as in Example 1 except that β-hydroxyethyl methacrylate in Example 1 was not used. The weight average molecular weight of the obtained resin was 47,000, and the resin solid content concentration of one polymerization solution was 3], wt%. This resin solution 1
00g (solid content: 31g), ) 160g of toluene and 62g of antimony-containing tin oxide powder having a particle size of 0.1 μm were placed in a ball mill and uniformly dispersed over 48 hours. This paint was applied to a transparent vinyl chloride plate in the same manner as in Example 1, and the surface of the resulting paint film was puff-finished and subjected to a prescribed performance evaluation test. The results are shown in Table 1.

A flask similar to Example 1 was charged with toluene and heated to 110°C. How to use Methyl methacrylate 108.7g, Hydroxyprobylmethac! J
A mixed solution t711iI of 1a3gg and 0.6g of polymerization initiator benzoyl peroxide was prepared and charged into a dropping funnel. A mixed solution of the monomer and polymerization initiator was dropped into the flask reactor over 2 hours under nitrogen gas. Then, the temperature 1W inside this reactor was lowered to 85°C.

Next, a solution prepared by dissolving 0.4 g of benzoyl peroxide in 20 g of toluene was dripped into the reactor from the dropping funnel over a period of 4 hours. After completion of dropping, further heat at 85℃ for 6
Continue reaction for time12. Toluene solution of copolymer f:? 4
It was. The polymerization rate was 99%. The weight average molecular weight of the copolymer was 58,000. Next, the above binder solution 2 (10 g (solid content 63.2 g), 320 g of toluene, and 140 g of antimony-containing tin oxide powder with a particle size of 0.1 μrn were charged into a ball mill, and mixed and dispersed for 48 hours. The resulting coating material Fully transparent acrylic board with a height of 2 μm
It was painted to look like this.

The coating film obtained by volatilizing Solvent E was subjected to a performance test in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2 The amount of tin oxide powder used in the paint preparation of Example 1 was
The same as in Example 1 except that the amount was 8 g. Table 1 shows the performance of the resulting coating film.

Comparative Example 3 Amount of tin oxide powder used in paint preparation Ki3 of Example 1
f: 124 g [Also 19, otherwise the same as in Example 1. The performance of the resulting coating film is shown in Table 1.

Examples 3 and 4 Toluene as a polymerization solvent shown in Table 2 and the monomers shown in Table 2 were charged into a four-rose bulbous flask reactor, and the temperature was raised to a predetermined polymerization temperature under a stream of gas. Next, a toluene solution of azobisimptiloni (IJ) as a polymerization catalyst was dropped into the reactor over a period of 2 hours. Next, a toluene d solution of the polymerization catalyst azobisisobutyronitrile was added dropwise over a period of 2 hours. The combination continued for another 8 hours, and a toluene-like solution of 1) 1 combination was produced. 4
It's 1. Next f.

Into a ball mill were placed 2 binder layers, 1 self-adding medium, and antimony-containing tin dioxide with a particle size of 1 μm.

Mix and disperse for 48 hours. 1↓1rarThe paint was applied to a fully transparent acrylic board so that the thickness of If: 3 μm71 was applied. Let the solvent evaporate? 4I et al J Mata Nuri IJAN 11
1.Subject to the ability test.

The results are shown in Table 1.

Example 5 Same as Example 1, 48 liters of toluene was added to the device d.
1111℃ in Ilk preparation and raw gas
The temperature was raised to . Next, methymethacrylate 1 and 44 (
1g, hydroxyoctyl methacrylate 601:
, 41 mixture of 2 g of benzoyl peroxide) It'
11-Place in IJ-to.

The mixture was added dropwise to the reactor over a period of 2 hours. Next, the temperature in the N reactor was lowered to 851°C, and penzoylperoxyl Ig dissolved in 720g of tolur was added dropwise over 54 hours. continue to respond to
A copolymer toluene solution with a solid content depth of 50 was obtained. Next, 300 g of the above toluene solution (solid content 1
50g), toluene 200g and particle size 0.1μ
20g of antimony-containing acid 11' tin powder was charged,
Mix and disperse for 48 hours. The resulting paint was applied to a transparent acrylic plate to a thickness of 2 μm. Let the solvent evaporate? The applied coating 1 (negative coating) was subjected to a performance test in the same manner as in Example 1. The results are shown in Table 1.

Example 6 Methyl methacrylate was placed in a polymerization apparatus similar to Example 1, and
Mixture of compounds corresponding to n-7~9 K 5 Nissan PE
-aso: manufactured by NOF Corporation) 70g and toluene 500
Then, 1 g of benzoyl peroxide was added as a polymerization catalyst to carry out polymerization. Polymerization start 5 o'clock r1
1, 2 g of benzoyl peroxide was added as a vc1fd catalyst. Further, the reaction was continued for 10 hours, and the copolymer toluene solution with a solid content concentration of 50% f:? 4(da...
Next, 300 g of the toluene solution (solid;
1511g for 1φ) + 200g of toluene)
O177 (1 μm antimony 1j tin oxide powder 2)
00ge preparation and dispersion of Wei a171 for 48 hours. 11+
1. Apply the prepared paint to a transparent acrylic machine to a thickness of 2 μm. Ta. Solvent (11 times)
1#' was subjected to the sex 1i1'2 test in the same manner as in Example 1.

The results are shown in Table 1.

Table 1 Table 2 Effects of the invention: The transparent paint for charging 1(ff+hi) of the present invention is ie+i
Forms a coating film that has Kif, K transparency and exhibits excellent band η protection effects. Its coating film, hardness,...
Even though I am suffering from severe pain, I am noticeably sore. In addition, since the static protection 1 is effective and transparent over bending, the conventional
III Purifier VCIt's [6 purifier haze area is extremely wide.

that's all

Claims (1)

[Claims] 1. Methyl methacrylate Φ 70-9) 3 moles R, H mo or C11s group + n = 1-10; and m = 3-
9) A paint binder made of a copolymer containing 2 to 25 moles of monomer represented by 9); and a conductive powder containing tin oxide as the main component and having a particle size of less than 0.2 μm. containing the conductive powder f for 0 parts by weight of the paint binder 1();
A transparent coating for preventing banding, containing 70 to 350 parts and 14 parts.