JPH02140255A - Coating composition - Google Patents

Abstract

PURPOSE:To obtain a coating composition having excellent mold releasability, resistant to the lowering of releasability even after repeated use and suitable for the coating of de-icing and de-snowing part, heat-roller, etc., by compounding specific amounts of a thermoplastic fluororesin and a fluorinated oil. CONSTITUTION:The objective composition can be produced by compounding (A) 100 pts.wt. of a thermoplastic fluororesin (e.g., tetrafluoroethylene polymer resin), (B) 1-10,000 pts.wt., preferably 10-1,000 pts.wt. of a fluorinated oil (e.g., perfluoropolyether oil) and, as necessary, (C) a liquid carrier (e.g., water or chlorofluorinated hydrocarbon).

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to coating compositions.

More specifically, the present invention relates to a coating composition with excellent mold release properties.

[Prior art] Conventionally, it has been used in the fields of release coats for frozen food refrigerating trays, release coats for freezer ice trays, anti-snow coatings for buildings, anti-snow coatings for road signs, and release coats for roll toners that are thermocompressed for photographic equipment. In some cases, a release coating material is used.

Conventionally, in the field of low-temperature release applications, particularly in the field of preventing icing and snow build-up, methods using compositions in which silicone resins are combined with alkali metals (Japanese Unexamined Patent Publication No. 59-25868), and perfluoroalkyl group-containing acrylic compositions have been used. A composition in which a thread polymer is combined with an alkali metal compound (Japanese Patent Application Laid-Open No. 61-95077)
) has been proposed. however,
These methods lack the durability of the film, and when used repeatedly, there are problems such as the mold release effect decreases, effective low icing power cannot be obtained, and the product becomes easily stained. Ta.

On the other hand, in the field of high-temperature release applications, such as thermocompression rolls for photographic machines, it is known to coat with polytetrafluoroethylene resin, perfluoroalkoxy resin, or the like. However, rolls coated with these resins have problems such as insufficient toner releasability, easy staining of the thermocompression roll, and insufficient offset prevention function.

[Problems to be Solved by the Invention] The present invention aims to solve the problems of the prior art described above. That is, the objective is to provide a coating composition that has excellent mold releasability at low to high temperatures and exhibits little deterioration in mold releasability even after repeated use.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and provides a coating composition characterized by containing a thermoplastic fluororesin and a fluorine oil. .

It is something to do.

In the present invention, the thermoplastic fluororesin used is one that is solid at room temperature. Such thermoplastic fluororesins include polytetrafluoroethylene resins (hereinafter referred to as
(hereinafter referred to as PTFE), perfluoroalkoxy resin (hereinafter referred to as PFA), perfluoroethylene-propylene resin (hereinafter referred to as FEP), ethylene-tetrafluoroethylene copolymer resin (hereinafter referred to as ETFE), polychlorotrifluoroethylene Resin (hereinafter referred to as PCTFE)
), ethylene-chlorotrifluoroethylene copolymer resin (hereinafter referred to as ECTFE), polyvinylidene fluoride resin (hereinafter referred to as PVDF), polyvinyl fluoride resin (hereinafter referred to as PVF), and the like. Among them, tetrafluoroethylene polymer resin, i.e., PT
FE, PFA, FEP, ETFE, etc. are preferably used because of their excellent mold release properties. Also, PTFE, P
F.A.

Perfluoro resins such as FEP have excellent mold releasability and are preferred. In particular, PF has excellent mold releasability and coating formation properties.
A. FEP is preferably employed.

Further, as the fluorine oil in the present invention, a compound containing fluorine and liquid at room temperature is employed. Specifically, oligomers, low polymers, etc. of fluorine-containing monomers are employed. More specific examples include perfluoropolyether, tetrafluoroethylene low polymer, and chlorotrifluoroethylene low polymer. These fluorine oils are commercially available under trade names such as Fomblin (manufactured by Montegisson), Flonloop (manufactured by Asahi Glass Co.), and Talitox (manufactured by DuPont). Among them, perfluoropolyether oil is preferably employed.

Further, the ratio of the thermoplastic fluororesin and the fluororesin oil is preferably 1 to 10,000 parts by weight, particularly 10 to 1,000 parts by weight of the fluororesin per 100 parts by weight of the thermoplastic fluororesin. If the fluorine oil content is less than the above ratio, good mold releasability will not be exhibited, and if it is too large, coating formation may become difficult, repeat durability may decrease, or sticky coating may occur on the coating surface. This is not desirable as it may cause

Further, the coating composition of the present invention may be in the form of a laminate, which is preformed into a film, or may be in the form of a paint containing a liquid carrier. In particular, coatings in the form of paints are preferred because they can easily coat articles with complex shapes. Here, examples of the liquid carrier include water, chlorofluorohydrocarbons, organic solvents such as alcohol, and the like. When the coating composition of the present invention is used in the form of a coating using a liquid carrier, it is preferable to add a stabilizer such as a surfactant from the viewpoint of coating workability.

Further, the coating composition of the present invention may contain various additives such as pigments and fillers within a range that does not impair the object of the present invention.

(Examples 1 to 10) Fomblin Y-25A diluted to 20 wt% with Freon R-113 was added to the solid content of PFA disversion using a paint gun capable of two-component mixed coating. 10 parts of oil in terms of weight ratio,
The discharge amount was adjusted to be 20 parts, 50 parts, and 100 parts, and the coating was applied to a brimer-coated aluminum test panel so that the film thickness after firing was 25 μm±5 μm. At this time, systems with a high amount of oil may cause latex destruction, so increase the atomization pressure depending on the situation, vaporize the Freon in the gas phase, and reduce the effect of latex destruction on the painted surface. Keep it to a minimum.

Similar operations were performed on PTFEI-Tubcoat enamel and FEP.
I went with the top coat enamel. However, the mixing ratio should be 10 to 50 parts, and the final top coat film thickness should be 18μ.
m±3 μm.

The firing conditions for the coating are PFA dispersion and PTFE.
Ten types of samples were prepared using l-tub coat enamel and FEP top coat enamel at 350°C x 15 minutes, 380"C x 10 minutes, and 350°C x IO minutes, respectively.

The icing power measurement test described later was conducted on these samples.

The results are shown in Table 1. For comparison, PFA,
Similar tests were conducted on PTFE and FEP coatings and are shown in the same table.

Table 1 Icing force measurement results As shown above, by adding fluorine-based oil to PFA, PTFE, and FEP coatings, the icing force decreases significantly, to the extent that they can be used as anti-icing coatings. This shows that it has anti-adhesion properties.

Icing force measurement test Aluminum plate coated with the composition of the present invention (60 x 60 x 3 m
m) Place an aluminum ring with a diameter of 30 mm and a height of 30 mm on top, and fill it with 5 mQ of ion-exchanged water.
Freeze for 30 minutes at °C.

The freezing sample was connected to a load cell, and a transverse shearing force (in a direction parallel to the test plate) was applied to the aluminum ring at a crosshead speed of 20 mm/min in an atmosphere of -18°C to measure the icing force.

(Examples 11 to 28) Fomblin Y-25A, YR, and Z-25 were each added to water to which a surfactant had been added at a weight percentage of 50%, and emulsified using a homogenizer.

This emulsion is mixed into PFA dispersion, PTFEt-tub coat enamel, FEP) tube coat enamel, E
5% solid content weight conversion ratio for TFE disversion, PCTFE disversion, P Kano disversion
, 10%, 20% added, and the film thickness after firing is PFA, P
15-25μ for TFE, FEP, ETFE
8 for PCTFE and PVDF so that
Appropriate pretreatment (primer coating, chemical conversion treatment,
Painted on an aluminum test panel that had been subjected to a blasting process. The coating film is cured by PTFE at 380°C x 10 min.
350℃ x 15 for PFA, FEP and PCTFE
320°C x 20 minutes for ETFE and PVDF.

The icing power of these systems was measured using the icing power measurement test described above. The results are shown in Table 2.

Table 2 Icing force measurement results As shown above, Fomblin Y-25AYR,Z
The icing power of the fluororesin coating film to which the -25 emulsion was added was significantly lower, ranging from one-third to one-tenth of that of the fluororesin coating film without additives, and the icing prevention effect was significantly reduced. It can be seen that the coating is of high quality. In particular, compared to the method of Example 1, the method can be applied with one liquid and does not require special coating equipment, which is very useful for industrial applications.

(Examples 29 to 31) Using two automatic air painting guns, put PFA disversion into one and Freon R-113 into the other.
A coating system is prepared in which Fomblin Y-25 diluted to 10% is mixed with PFA dispersion and Fomblin oil during atomization.

This coating system is used to create a mixed coating of PFA and Fomblin oil. The construction sample used was a cold-stretched ordinary steel plate with a width of 90 cm, a length of 180 cm, and a thickness of 1 mm, which was subjected to blasting treatment and then coated with a primer. The discharge amount was 100 g/min for PFA dispersion, 10 g/min for Fontprin oil, 30 g/min and 70 g/min, and the discharge pressure and atomization pressure were 1 kg/cm2 and 2 kg/cm2, respectively.
It was painted at kg/cm2. Film thickness after firing is 20μm±
The thickness was adjusted to 3 μm. The amount of each oil added is PF
A conversion ratio of approximately 4 parts, approximately 16 parts, and approximately 30 parts to PFA
corresponds to the section.

A four-stage tunnel furnace is used to cure the coating film, and the atmospheric temperature in each zone is 120"C for the first zone and 30"C for the second zone.
0℃, the third zone is 350℃, the fourth zone is 300℃,
The length of each zone was 180 cm. Since the conveyor speed was 30 cm/min, the baking time was 24 minutes in total.

Regarding this sample, the snow accretion prevention performance and icing prevention performance were evaluated. The icing force was measured using the same test method as in Example 1. For the snow accretion test, we piled up artificial snow and measured the temperature at which the compressed snow would automatically begin to slide. First, the artificial snow was prepared using a horizontally placed sample (900 mm
30cm installed on top of 1800mm x 1mm)
Snow was deposited in an aluminum ring measuring φ (inner diameter) x 30 cm (height). The snow is piled up to a height of 30 cm, and after the snow is piled up, it is compacted by applying a load of 10 g/cm2. The atmospheric temperature during snowfall and loading was set at -1θ°C, and after the load was applied for 10 minutes, it was moved to a cold room at -18°C and left for 24 hours.

This sample plate was heated from the opposite side of the sample plate, the temperature was raised from -18°C at a heating rate of 3°C/min, and the temperature at which it started to slide naturally was measured. Similar tests were conducted on PTFE and PF for comparison.
A similar iron plate coated with A was tested. The results are shown in Table 3.

Table 3 Results of snow accretion prevention performance test As shown in Table 3 above, in the coating system containing Fomblin oil, the temperature at which artificial snow starts falling automatically is lower than that of Comparative Examples 1 and 2 with no oil added. It is clear that the snow accumulation prevention performance is excellent. In addition, the icing power was also measured in Example 29.
The coating film of ~31 has a icing power of 1/2 ~ 30 that of Comparative Example 1.
It is extremely low (1/2) and has excellent anti-icing performance.

(Examples 32 to 34) Fomblin Y-25A and Z-25 were added to water to which a surfactant was added so that the weight percentage was 50%, and after emulsifying with a homogenizer, the particles with a particle size of 3 mmφ were added.
Stir in a ball mill containing glass peas for 2 hours to further refine the emulsified particles. This emulsion is mixed into PFA dispersion, PTFE top coat enamel, F
EP top coat enamel with a solid content weight conversion ratio of 1
Add 5% and perform appropriate pre-treatment to obtain a top coat and adhesion so that the film thickness after firing is 15 to 25 μm.
Painted on an aluminum test panel that had been treated with (blimer coated, blasted). PTFE cures the coating film with 3
80℃XIO min, 350℃X for PFA and FEP
The test was carried out for 15 minutes.

Regarding these coating films, an evaluation test was conducted for the anti-frost performance. Evaluation of the test was carried out by observing the appearance of the frost and the adhesion of the frost. The frost production method is to keep the wall temperature at 110℃.
Ion-exchanged water is placed in a tank, and a stirring blade is rotated at a high speed of 600 rpm to perform heat exchange. The heat-exchanged ion-exchanged water is applied to the test panel at a discharge pressure of 3.0 kg/cm'' in a low-temperature room with an ambient temperature of -18°C to deposit frost.The other method is to deposit frost at an ambient temperature of -15°C. Two methods were used to grow frost on the test panel by leaving the test panel with the coating surface at 18℃ for 2 hours in a cold room adjusted to saturated water vapor pressure.The spray method was used to evaluate the adhesion of frost. The force required to remove frost from the test panel using a 10 cm wide scraper was measured for the prepared sample.The measurement atmosphere temperature was -18°C.

The results are shown in Table 4. For comparison, the results of similar tests performed on oil-free PFA coatings, PTFE coatings, FEP coatings, and uncoated aluminum test panels are also listed in the same table.

Table 4 Evaluation results of frost adhesion prevention performance, Appearance observation evaluation A: Almost no frost is observed on the surface.

B: 50% of the surface is covered with frost.

C: The entire surface is covered, but no continuous layer formation is observed.

D=The entire surface is covered and a continuous layer is formed. However, the frost has not turned into ice.

E: The entire surface is covered and a continuous layer is formed. Furthermore, the frost has turned to ice.

As shown in Table 4, in the case of oil-containing coating systems (Examples 32-34), frost adhesion and frost adhesion were also lower in the case of oil-containing systems (Comparative Examples 1-3) and aluminum. It is significantly reduced compared to the panel (Comparative Example 4), and can be used as an anti-frost coating.

(Examples 35-36) Using two automatic air painting guns, one of them was filled with PFA disversion or PTFE top coat enamel, and the other was filled with paint diluted to 10% (by weight) with Freon R-113. Add Brin Y-25 and atomize P.
Create a coating system that mixes FA disversion or PTFE top coat enamel and von Prin oil.

This coating system is used to create a mixed coating of PFA or PTFE and Fomblin oil. The construction sample used was an aluminum plate measuring 60 mm x 90 mm and having a thickness of 2 mm, which had been subjected to blasting treatment and then coated with brimer.

The discharge amount was 100 g/min and 20 g/min for PFA disversion and Fontprin oil, respectively, and the discharge pressure and atomization pressure were 11 (g/cm2 and 2 kg/cm2, respectively).The film thickness after firing was 20 μm±. The thickness was adjusted to 3 μm.

The curing conditions for the coating film were 350°C for 15 minutes for the PFA coating system and 3808CXS minutes for the PTFE coating system.

Regarding this coating system, an evaluation test was conducted to evaluate the release performance of the toner. Evaluation is performed by testing the adhesion of fused toner and toner fixing performance. To measure the adhesion of molten toner, put 1 g of black toner into a ring with an inner diameter of 10 mm that is placed on a sample placed horizontally, and place it in a constant temperature chamber of a tensile tester at 200°C for 10 minutes to fully melt the toner. After that, 1
The sample was cooled to 50° C. at a rate of 10° C./min, and after reaching the set temperature, it was left to stand for 10 minutes, and then the adhesion between the sample and the toner was measured using a tensile tester. In addition, in the fixing performance evaluation test, the black toner was applied once on PPCm paper.
Using a cross net, remove the coated sample to a thickness of approximately 200 μm (thickness of the film after melting) in cm width, and place the coated sample on top of it.
A load of 50 g/cm2 was applied for 9 hours, and then the degree of residual toner on the surface of the painted sample was observed. Table 5 shows the results.
Shown below.

Table 5 Evaluation results of toner release performance (black toner) Appearance evaluation A: No toner remaining B: Traces of toner remaining.

C: Toner remains on about 10% of the contact area.

D=Toner remains on about 50% of the contact area.

E: Toner remains on the front surface of the contact portion.

As shown in Table 5, the oil-containing fluoropolymer coatings (Comparative Examples 35.36) have significantly reduced toner adhesion compared to the oil-free coating systems (Comparative Examples 1.2). .

(Example 37) Fonprin Y diluted to 20% with Freon R-113
-25 is applied with a paint gun to the sample surface that has been previously coated with PFA resin and dried. The discharge fee is 2
0g/10 seconds, and the amount of oil was 8% by weight relative to the PFA resin. This sample
After sufficiently drying at 00°C, it was fired at 330°C for 5 minutes.

Regarding this sample, the release performance of the adhesive was evaluated. For evaluation samples, a ring with an inner diameter of 10 mm was placed on the sample surface, and an appropriate amount of epoxy adhesive, vinyl chloride adhesive, styrene-butadiene adhesive, or chloroprene adhesive was placed in the ring and left for 24 hours. and adhere it to the sample surface. This sample was tested using a universal testing machine (manufactured by Orientic Aji).
against the sample surface at a crosshead speed of 0 mm/min.
The adhesive force was measured by pressing from the horizontal direction. In addition,
For comparison, a similar test was conducted on a PFA coating that did not contain oil.

The results are shown in Table 6.

Table 6 Adhesive release evaluation results As shown in Table 6, the adhesion force of adhesives to PTA resin coatings containing oil is 1/2 to 1/3 of that of coating systems that do not contain oil. Adhesive strength has decreased. PFA coating film is the best existing material for preventing adhesive adhesion, but this time, oil-containing PFA
It can be seen that the coating is an even 2-3 times better material.

[Effects of the Invention] The coating composition of the present invention has excellent mold releasability, and even after repeated use, the deterioration in mold releasability is extremely small. Such compositions can be used to prevent icing, snow accretion, heat rollers, frozen foods, etc.

Claims (1)

[Scope of Claims] 1. A coating composition characterized by containing a thermoplastic fluororesin and a fluorine oil. 2. The coating composition according to claim 1, wherein the thermoplastic fluororesin is a tetrafluoroethylene polymer resin. 3. The coating composition according to claim 1, wherein the fluorine oil is perfluoropolyether oil. 4. The coating composition according to claim 1, wherein the fluorine oil is contained in an amount of 1 to 10,000 parts by weight per 100 parts by weight of the thermoplastic fluororesin. 5. The coating composition according to claim 1, further comprising a liquid carrier.