JPS61178442A - Powder coating frit and powder coating method - Google Patents

Abstract

PURPOSE:A frit, consisting of an R2O3 component containing Al2O3 at a specific ratio in a specified total amount, R2O component such as Na2O, etc., RO component such as MgO, etc., and MO2 component containing SiO2, and having improved chemical and hot water resistance. CONSTITUTION:A powder coating frit consisting of an R2O3 component containing essentially 3.1-12.0wt% Al2O3 in 3.1-35.0wt% total amount, such as Al2O3, B2O3 or Sb2O3, R2O component such as Na2O, K2O, Li2O, etc., RO component such as MgO, CaO, ZnO, BaO, SrO, etc., MO2 component containing essentially SiO2 such as SiO2, TiO2, ZrO2, SnO2, etc., and if necessary, with another secondary component added. The resultant frit is powdered and electrostatically applied to the base metal surface. The above-mentioned frit has improved adhesion and further improved chemical and hot water resistance. Therefore, enamel products having an enamel layer with improved chemical and hot water resistance are obtained by using the above-mentioned frit.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a powder coating frit with excellent chemical resistance and hot water resistance, and a powder coating method using this frit (prior art) Nohoru and Ufurit are usually wet-pulverized with clay to create a glaze, which is then applied to the metal surface by dipping, spraying, etc., and then fired.
Powder coating, which uses electrostatic voltage to attach frit particles to metal surfaces, has been in the spotlight for several years.

In this technique, a frit with high electrical resistance is used to improve the adhesion of frit particles, and a powder coating frit whose surface is coated with an organic material with high electrical resistance such as alkoxysilane or organopolysiloxane is used. It is used. (For example, Japanese Patent Application Publication No. 52-9
(Publication No. 8721, Japanese Unexamined Patent Publication No. 7005/1987) (Problems to be solved by the invention) However, although such conventional powder coating frits tend to have a mirror-like glazed surface, they have extremely poor chemical resistance and hot water resistance. Because of its poor quality, it was considered unsuitable for use in equipment used under harsh conditions, such as boilers, bathtubs, and sinks. Therefore, there has been a need for a frit for powder coating that has high adhesion suitable for powder coating and has excellent chemical resistance and hot water resistance, and a powder coating method using the frit.

(Means for Solving the Problems) The present invention provides A 1 t O of 3.1 to 12.0% by weight.
In addition to RzO2 components such as Al2Oz, B2Os, and 5b2Oz, which essentially contain 3.3 and the total amount is 3.1 to 35.0%, R2O components such as NatOlK, 01Lit○, and MgO1CabSZnO, Bad, SrO, etc. R of
SiO□, Ti which essentially contains O acid component, Sing
A first invention regarding a powder coating frit characterized by comprising a Moz component such as Ox % Zr0z, 5not, and other subsidiary components added as necessary, and a frit of the first invention and a second invention relating to a powder coating method characterized in that the powder is pulverized and then electrostatically adhered to the surface of a metal substrate.

A I! which is essentially contained in the first invention! O
S is a component that increases the chemical resistance and hot water resistance of the frit, and if it is less than 3.1%, the desired effect cannot be obtained.
If it exceeds 12.0%, acid resistance will deteriorate, so 3.1
It needs to be in the range of ~12.0%.

In addition, B t O3 other than A 1 z Ox, S b
The R:03 component such as tOs is the same as A1. It has the same effect as R2O, but the total amount of R2O components is 35
．． If it exceeds 0%, the acid resistance tends to deteriorate significantly, so the total amount needs to be 3.1 to 35.0%. Na
The R1o component such as go, Kz01LitO is a component for facilitating the melting of the frit and lowering the melting point.
It is desirable that the total amount is 0.5% or more. However, if the total amount exceeds 30%, strength, chemical resistance, and hot water resistance will decrease, so the total amount of RzO components should be in the range of 0.5 to 30%. It is preferable to do so. In addition, among the R t O components, Na t O in particular is a component that influences the electrical properties of the frit, and in order to give the frit stable chargeability and adhesion suitable for powder coating frits, 1.
MgO1CaO1, which is preferably 5.5% or less
ZnO1BaO.

RO acid components such as SrO are generally components for improving the melting properties of frits, but if the total amount exceeds 25%, hot water resistance tends to decrease, so it is preferable to keep it at 25% or less. *StO□ is a major component. It is a glass-forming oxide, and if it is less than 35%, deterioration of hot water resistance and acid resistance is observed.
If it exceeds 65%, the frit becomes poorly soluble, so the ratio is 35 to 6.
Preferably, the range is 5%, and Stow, T
For the same reason, it is desirable that the total amount of Mox components such as iO□ and ZrOzsSnO be 35 to 85%. In addition, the frit of the present invention contains 0.5 to 10
% F, 10% or less Pt0s 13% or less M o O
A subcomponent containing one or more of the following may be added as necessary. F of 0.5% or more is effective in improving the meltability of the frit, but if it exceeds 10%, hot water resistance and acid resistance deteriorate. PtOs is effective in lowering the melting point and has little viscosity drop at high temperatures, so it is a preferred component to obtain a frit that can be fired at low temperatures and is difficult to burn out. However, if it exceeds 10%, chemical resistance and heat resistance deteriorate. This causes deterioration of water quality. MoO3 is a component that improves acid resistance, but if it exceeds 3%, foreign crystals will occur on the surface, so it is desirable to keep it below 3%.In addition, it can be used as a pigment to give various colors to the frit. Co
O, NiO5Mn0. , Cr2Ox , Foxes,
The total amount of one or more of Cub, VtQ, etc. is 1
It is added externally in a range of 2% or less.

The frit of the present invention having the above composition exhibits excellent adhesion when powder coated, as is clear from the examples described below, and has excellent chemical resistance and hot water resistance. By pulverizing it and electrostatically attaching it to the surface of a metal base, it is possible to obtain an excellent enamel product that can withstand harsh usage conditions.

(Example) Raw materials were prepared to have the compositions of Examples 1 to 12 and Comparative Examples 13 to 26 in Table 1, melted at 1200 to 1300°C, and rapidly cooled to produce frits.

These frits were used in Examples 1 to 12 and Comparative Examples 13 to 1.
Item No. 9 was treated with a coupling agent to form a frit for powder coating, and then applied with an electrostatic voltage of 1,100 kV using an electrostatic powder gun to a steel plate on which a lower glaze had been baked before being glazed and fired. On the other hand, the frits of Comparative Examples 20 to 26 included 100 parts by weight of the frit, 6 parts of clay, 0.2 parts of potassium chloride,
Add 45 parts of water, grind in a mill, and put 5g into a 200 mesh sieve.
The slip, which was adjusted so that it would remain, was glazed on a similar steel plate by spraying, dipping, etc., then dried and fired. The acid resistance spot test, weight loss acid resistance test, weight loss resistance alkali test, and weight loss hot water resistance test were conducted on each test piece obtained in this way. As shown in Table 2, the frits of Examples 1 to 12 were showed excellent properties. In addition, each test method is as follows.

Table 2 (1) Acid resistance spot test JIS R43015.9.1 A 10% citric acid solution was placed on a 3x3cs three-ply filter paper placed on the test piece using a method similar to the room temperature spot test method using citric acid in JIS R43015.9.1. Drop it with a dropper, moisten the filter paper thoroughly, and then leave it at room temperature for 1 hour.
Leave it for 5 minutes and evaluate the change in surface gloss.

(2) Weight loss value of the enamel layer (liquid phase test piece) after placing the test piece in 450 ml of a 6% citric acid solution and holding it in a boiling state for 6 hours using a test device similar to Acid Resistance Test 150-2733. Measure. The measured value is the average value of three test pieces and is expressed in units of g/rrl.

(3) Weight loss hot water resistance test Using the same test equipment as in (2), the test piece was placed in 450 ml of pure water and kept in a boiling state for 48 hours, then the weight loss value of the enamel layer of the liquid phase test piece and the gas phase test piece. Measure. The measured value is the average value of three test pieces and is shown in units of g/nf/day, where the numerator is the data of the liquid phase test piece and the denominator is the data of the gas phase test piece.

(4) Weight loss resistance test Using a test device based on ISO-2734, the test piece was placed in a 5% sodium birophosphate solution, kept in a constant temperature bath at 90°C ± 1°C for 6 hours, and then the enamel layer ( Measure the weight loss value of liquid phase test piece). The m constant value is the average value of 3 test pieces and is expressed in units of g/rrr.

(5) Adhesion evaluation Powdered frit 100 Tsuru x 100 tm
1.2 was electrostatically adhered to a steel plate for Tsuru enameling, and an impact of 0.28 ksr/j was applied without firing, and the amount of frit falling was measured, and the percentage of frit that did not fall was expressed in %.

(Effects of the Invention) As is clear from the above examples, the frit for powder coating of the present invention has excellent adhesion suitable for powder coating, and has excellent chemical resistance and hot water resistance. Therefore, according to the powder coating method of the present invention using this frit, it is possible to automatically and mechanically produce an enamel product having an enamel layer with excellent chemical resistance and hot water resistance. Therefore, according to the present invention, it is possible to easily enamel boilers, bathtubs, sinks, etc., to which powder coating methods could not be used in the past, using the powder coating method. Therefore, the present invention eliminates the problems of the conventional technology and greatly contributes to the development of industry.

Patent applicant Nippon Frit Co., Ltd. (Voluntary author of procedural amendments) 1985 Patent Application No. 15721 2 Name of the invention Powder coating frit and powder coating method 3 Relationship with the person making the amendment Patent applicant Address Aichi Prefecture 36-50 Asahicho 1-chome, Handa City
, Contents of amendment (1), "200 mesh sieves" on page 8, line 9 of the specification
There is a 200 mesh sieve using r50cc slip.
and correct it.

(2) On page 8, line 10 of the specification, the phrase "adjusted slip" is amended to read "adjusted slip."

(3) The phrase "of the present invention" is deleted from page 14, line 18 of the specification.

(4) The words "automatically or mechanically" on page 14, line 19 of the specification are deleted.

that's all

Claims (1)

[Claims] 1. Al_2O_3 which essentially contains 3.1 to 12.0% by weight of Al_2O_3, and the total amount is 3.1 to 35.0%.
R_2O such as 2O_3, B_2O_3, Sb_2O_3
In addition to the _3 components, Na_2O, K_2O, Li_2O
R_2O components such as MgO, CaO, ZnO, BaO
, an RO component such as SrO, an MO_2 component such as SiO_2, TiO_2, ZrO_2, SnO_2, etc. that essentially contains SiO_2, and other subsidiary components added as necessary. Frit 2 for coating, R_2O component is 0.5-30% in total and contains 15.5% or less Na_2O, RO component is 25% or less in total, MO_2 component is in total amount 35-8%.
5% and contains 35-65% SiO_2, with secondary components of 0.5-10% F and 10% or less P_
The frit for powder coating according to claim 1, which contains 2O_5 and 3% or less of MoO_3. 3. CoO, NiO, MnO_2, Cr_2 as pigments
The frit for powder coating according to claim 1 or 2, wherein one or more of O_3, Fe_2O_3, CuO, and V_2O_5 are externally added in a total amount of 12% or less. 4. Al_ which essentially contains 3.1 to 12.0% Al_2O_3 in terms of weight ratio, and the total amount is 3.1 to 35.0%.
R_2O such as 2O_3, B_2O_3, Sb_2O_3
In addition to the _3 components, Na_2O, K_2O, Li_2O
R_2O components such as MgO, CaO, ZnO, BaO
, a powder coating frit consisting of an RO component such as SrO, an MO_2 component such as SiO_2, TiO_2, ZrO_2, SnO_2, etc. that essentially contains SiO_2, and other secondary components added as necessary. A powder coating method characterized by powdering and electrostatically adhering it to the surface of a metal base.