JPH03227333A - Apparatus for treating surface of molded resin product - Google Patents

Abstract

PURPOSE:To obtain an apparatus for treating the surface of a molded resin product, equipped with ultraviolet fluorescent lamps and low-pressure mercury lamps for irradiation of ultraviolet rays having continuous spectra with main wavelengths within specific regions together and capable of improving coating properties, printability and adhesion of a resin. CONSTITUTION:A material 7 to be treated (e.g. a bumper made of polypropylene-based resin) is fixed in a treating chamber 3 of an apparatus 1 for surface treatment having a light source (L) using ultraviolet fluorescent lamps 16 and low-pressure mercury lamps 15 for irradiation of ultraviolet rays having continuous spectra with main wavelengths within the region of 254 to 400nm together supported on a light source supporting frame 13 and surface treatment of the material 7 to be treated such as a molded resin product is carried out by irradiating the material 7 with the ultraviolet rays from the light source (L) while heating the material 7 to be treated by supplying hot air from a hot air feeding mechanism 10 composed of an air blasting motor 8 and a heating heater 9, dispersing the hot air with a dispersing honeycomb 12, then passing the hot air through a hot-air honeycomb 4 and feeding the air into the treating chamber 3.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a surface treatment device for resin molded products, and particularly for hydrophobic resin molded products made of polypropylene or polyolefin resins (for example, resin bumpers of automobiles). , resin cowlings for motorcycles, resin engine covers for outboard motors, etc.).

b. Prior Art Recently, polypropylene or polyolefin resin molded products have been widely used as automobile parts such as bumpers. However, this type of resin molded product has no polar group in its molecules, is hydrophobic, and has an inert surface, so it has the disadvantage of poor paintability, printability, and adhesiveness.

For this reason, conventionally, when painting a polypropylene or polyolefin resin bumper, a primer made of chlorinated polyolefin and toluene was applied to the bumper surface to improve adhesion to the bumper surface, and then the paint was applied. It is normal to do so. However, although the method of applying paint through a primer provides reliable adhesion, the primer itself is expensive and there are problems with productivity, such as extra steps such as applying and drying the primer. . Therefore, polypropylene or
It is desired to eliminate the need for a brimer by subjecting a polyolefin resin bumper to an appropriate surface treatment.

By the way, several treatment methods have been proposed to improve the adhesion of a coating film on the surface of a resin molded article. For example, Utility Model Application Publication No. 64-30338 and Japanese Patent Application Publication No. Hei 1
-216824 includes a preheating chamber for a molded body, a solvent chamber for bringing an ultraviolet absorber into contact with the surface of the molded body, and a main wavelength of 1.
A surface treatment apparatus for a molded body of a low-active polymer material has been proposed, which includes an irradiation chamber equipped with a low-pressure mercury lamp that irradiates ultraviolet rays of 85n+w, and a transport mechanism that transports the molded body to each of the chambers. In addition, JP-A No. 62-79235 discloses that after a polypropylene resin molded product is brought into contact with ultraviolet absorbing benzene or a benzene-based solvent heated to 30 to 80°C for 10 seconds to 15 minutes, By performing surface treatment by irradiating the surface with ultraviolet rays with a dominant wavelength of 185 nm using a surface treatment device using a low-pressure mercury lamp as a light source,
A surface treatment method has been proposed to improve the adhesion of a coating film on the surface of a resin molded article.

The reasons why low-pressure mercury lamps are used as the light source for ultraviolet irradiation surface treatment equipment are that the irradiation treatment equipment can be manufactured at low cost, running costs are low, and the dominant wavelength is 254 nm of the high-energy mercury emission line. Also, surface treatment efficiency is high due to irradiation with ultraviolet light having a short wavelength of 185 nm.

C1 Problems to be Solved by the Invention However, the conventional surface treatment apparatus and method as described above have the following problems.

In other words, the processing wavelength for polypropylene resin is 295n.
However, this type of ultraviolet surface treatment equipment and method uses only a low-pressure mercury lamp that irradiates ultraviolet rays in the emission line spectrum with dominant wavelengths of 254 nm and 185 nm. No surface treatment effect can be obtained by ultraviolet rays in the wavelength range. Therefore, when surface treating a resin bumper or the like using this type of apparatus and method, the treatment efficiency is low and the treatment is insufficient. Moreover, there are problems such as uneven processing.

Furthermore, since only ultraviolet rays in the bright line spectrum of strong energy are irradiated, cross-linking reactions, which are disadvantageous for surface treatment, proceed more than surface treatment reactions such as the formation of polar groups and carbonyl groups to improve paintability, resulting in a sufficient surface treatment effect. There is also the problem that it is not possible to obtain

The present invention was made to solve these various problems, and its purpose is to obtain a sufficient surface treatment effect and improve paintability, printability, and adhesion. It is an object of the present invention to provide a surface treatment device for resin molded products that can be used to treat resin molded products with less unevenness.

d. Means for Solving the Problems In order to achieve the above-mentioned object, in the present invention, 25
A light source is used, which is a combination of an ultraviolet fluorescent lamp that emits continuous spectrum ultraviolet light having a dominant wavelength in the range of 4 to 400 nm, and a low-pressure mercury lamp.

The background to devising such a configuration is as follows.

Figure 3 shows data on the degree of surface treatment for polypropylene resin bumper materials for each wavelength of UV irradiation with equal energy (the test was conducted using a spectroscopic irradiation device, and the degree of surface treatment was determined using FTIR and ATR). As is clear from Figure 3, the degree of surface treatment improves as you go from 400 nm or less to the shorter wavelength side. It can be seen that ultraviolet rays also have a large effect on surface treatment. Therefore, instead of only irradiating ultraviolet rays with specific wavelengths of 254 nm and 185 ns like a low-pressure mercury lamp, it is better to irradiate a continuous spectrum of ultraviolet rays in the 254 to 400 nm range to have a higher surface treatment effect and reduce treatment unevenness. In addition, we believe that this will reduce cross-linking reactions that are disadvantageous to surface treatment, which occur when irradiating only ultraviolet rays with specific strong-energy emission line spectra, so we developed a special ultraviolet fluorescent lamp that irradiates continuous-spectrum ultraviolet rays with a dominant wavelength in the 254-400 nm region. He invented the combined use of a low-pressure mercury lamp and a low-pressure mercury lamp as a light source for a tree surface treatment device.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a surface treatment device 1 for a polypropylene resin bumper (25% ethylene propylene rubber), which has excellent economic efficiency and impact resistance.

As shown in Figure 1, the housing (processing tank) of this device l
The processing chamber 3 within the chamber 2 is divided into upper and lower compartments 5 by means of a rectifying honeycomb 4.
6, and a polypropylene resin bumper 7, which is an object to be treated, is fixedly arranged above the air regulating honeycomb 4.

A hot air supply mechanism 10 consisting of an air blower motor 8 and a heating heater 9 is provided at the center of the bottom of the housing 2. Dispersed honeycombs 12 are arranged. In addition, in the processing chamber 3, a light source support frame 1 is provided above the air conditioning honeycomb 4.
3 is provided, and the light aL is supported by this support frame 13. In addition, in FIG. 1, 14 is an exhaust gas regulator disposed in the housing 2.

The above-mentioned light source is composed of low-pressure mercury lamps 15 and special ultraviolet fluorescent lamps 16 arranged in parallel at regular intervals. Two special ultraviolet fluorescent lamps 16 are arranged. The total number of low-pressure mercury lamps 15 and special ultraviolet fluorescent lamps 16 is 21, and they are installed at a ratio of 2:1. The low-pressure mercury lamp 15 and the special ultraviolet fluorescent lamp 16 have a rated tube diameter of 32.5 mm and a tube length of 630 mm.
wm, output of 30W is used.

Here, regarding the special ultraviolet fluorescent lamp 16, it is desirable to use quartz glass that has good transparency for ultraviolet rays of 400 nm as its bulb. ) is not allowed.

Further, the shape of the bulb of the special ultraviolet fluorescent lamp 16 may be a straight tube type, a U-shape, a ring shape, a flat plate shape, a light bulb shape, etc., but is not particularly limited. In this embodiment, a straight pipe type tube is used. In addition, as a phosphor, 254~
There is no particular limitation as long as it is a phosphor that irradiates continuous spectrum ultraviolet light having a dominant wavelength in the 400 n*Sl region.

For example, as a phosphor, Caz(POa)z・KC
l: Tf, (Ba, Mg+ zr+) 3st, o?
:pbSSrO・4BzOs :Pb, Sr0・2
AfzOs: pb, (Ca, Zn)s(PO4
)i: Tl.

(Ca, Mg)s(POn)z: Tl, CaKP
O4:Tj! ,, Ba5ins: (Tf, Pb,
Sb), Ca5(PO4)z: Tl, Ba5izO
s: Pb.

BaFSiOs: Pb, Ba5ins: Tl
, Ca5(POa)t:Ce.

Ca5(PO4)z: Th,, YPOs:Ce −
, YPOn:Th% Sr*(Box)z:Pb,
(Ba, Sr, Mg, Zn)ssLOt:Pb
, (Sr, Mg)FBz(1+, s:Eu, (
Ba, Mg+ Zn, Ca)zsio4:Pb,
(Ba, MgZn+ Ca)zsiom:As, (
Mg+Ba, 5r)zPz07:Sn, (SrM
g) zPzov:Eu, (Ba, Sr+Mg)S
in,:Pb% (Ba, MgSr, Zn+C
a) SiOs:Pb, 5rB40J:Eu, LaP
O4:Ce etc. can be mentioned.

Note that it is desirable to use one or more types of phosphors to adjust the wavelength distribution in accordance with the surface treatment characteristics of various resin materials.

It is advantageous to make the peak wavelength as short as possible in terms of the treatment effect, but in order to treat the surface of the resin bumper 7 evenly and uniformly, it is necessary to irradiate ultraviolet rays in the wavelength range of 254 to 400 nm as uniformly as possible. is desirable.

Table 1 details of the special ultraviolet fluorescent lamp 16 used in this example.
Shown below.

Table 1 Special ultraviolet fluorescent lamp 16 has a mercury emission line of 305 to 31
(Ca, Zn)s(POa)z:Tl 10
320 ~ more than commercially available health line fluorescent lamps that use 0%
Increase the amount of ultraviolet rays with wavelengths around 400 nm to 265~
To uniformly emit ultraviolet rays in the 400nm region, a continuous spectrum of ultraviolet rays with a peak wavelength of 360 to 380n* is emitted to the health line phosphor (Ca, Zn)s(POa)z:Tl using a mercury emission line. Plantalight phosphor 5rB40tF: Eu was mixed. The lamp bulb is made of quartz glass, which has good UV transparency.

Next, the operation and effect of the surface treatment apparatus 1 of this example will be described. First, when hot air 17 is blown into the lower chamber 6 of the processing chamber 3 from the hot air supply mechanism 1o, this hot air 17 passes through the dispersion honeycomb 12 and the air conditioning honeycomb 4 sequentially to the upper chamber 6 of the processing chamber 3.
As a result, the temperature in the upper chamber 5 and the ambient temperature of the resin bumper 7 are kept constant. In this case, the temperature of the air atmosphere during the surface treatment of the resin bumper 3 is preferably in the range of 60 to 90°C. this is,
This is to further enhance the surface treatment effect due to the contact action of the metal contained in the ultraviolet absorbing pigment mixed into the resin molded product and the interaction of the pigment, dispersant, antioxidant, etc.

Under such temperature conditions, the surface of the resin bumper 7 is irradiated with ultraviolet rays by turning on the light source. At this time, the irradiance of the low-pressure mercury lamp 15 (254 nm bright line spectrum, which accounts for about 95% of the total irradiation energy) and the spectral irradiance of the special ultraviolet fluorescent lamp 16 are the second
The result will be as shown in the figure. As shown in FIG. 2, the special ultraviolet fluorescent lamp 16 starts at around 285 nm,
It has two peak wavelengths around 10ns and 365nm,
Ultraviolet rays are emitted up to around 415nm, and 265nm
1) It is observed that ultraviolet rays in the wavelength range of 400 nm to 400 nm are uniformly radiated.

Thus, the surface of the resin bumper 7 is irradiated with ultraviolet rays having a spectral irradiance obtained by mixing the irradiances of the special ultraviolet fluorescent lamp 16 and the low-pressure mercury lamp 15 shown in FIG.

Generally, on the surface of most resins, the interaction of additives such as pigments, dispersants, and antioxidants contained in the resin promotes surface treatment reactions, so-called photo-thermal oxidative deterioration reactions.

The reaction formula for resin surface treatment by ultraviolet irradiation is shown below.

RH (polymer) +A・→R・10AH R・10t−+ROO ROO・+RH→Root (+R・(generation of polar group) R
OOH→Generation of carbonyl group, main chain cleavage In other words, surface treatment of the resin (resin bumper 7) by ultraviolet irradiation means that energy such as light and heat is applied to the hydrophobic resin surface, which has no polar groups in the molecule. The surface is activated, causing a radical chain reaction, so-called photo-thermal oxidation reaction, and polar groups, carbonyl groups, etc. are generated on the resin surface. In addition, as the reaction progresses further, main chain scission etc. occur. Therefore, the wettability of the resin surface is improved, and the paintability, printability, and adhesion of the molded product are improved.

However, when the surface treatment of the polypropylene resin bumper 7 is performed using only the low-pressure mercury lamp 15 as the light source as in the past, the wavelength range of ultraviolet rays that is effective in surface treatment of the polypropylene resin covers the entire range of ultraviolet rays of 400 n+s or less. Since the low-pressure mercury lamp 15 irradiates only ultraviolet rays with a bright line spectrum having a specific dominant wavelength of 254r++w and 185 nm, there is no treatment effect for ultraviolet rays in other wavelength ranges, resulting in poor treatment effects and uneven treatment. In addition, since only ultraviolet rays in the bright line spectrum of strong energy are irradiated, cross-linking reactions, which are disadvantageous for surface treatment, proceed to their full potential rather than surface treatment reactions such as the formation of polar groups and carbonyl groups to improve paintability. The treatment effect cannot be obtained.
However, in this embodiment, since not only the low-pressure mercury lamp 15 but also the special ultraviolet fluorescent lamp 16 is used as a light source, not only the ultraviolet rays at specific wavelengths of 254n* and 185nm, but also the continuous spectrum in the 254-400nm region are used. Since ultraviolet rays are also irradiated, the surface treatment effect can be enhanced. Note that if only the special ultraviolet fluorescent lamp 16 is used as a light source, the ultraviolet energy irradiated is too mild and surface treatment takes too much time, so a low-pressure mercury lamp I5 is also used in order to streamline the irradiation work. It is.

Next, a specific example in which the surface treatment of the resin bumper 7 was performed using the surface treatment apparatus 1 according to the present invention will be described.

After washing the polypropylene resin bumper 7, which has been injection molded with "shiba" liquid, for one minute with trichloroethane steam, it is immediately placed in the surface treatment apparatus 1 equipped with a special ultraviolet fluorescent lamp 16 and a low-pressure mercury lamp 15 as shown in FIG. The distance between the light source and the resin bumper 7 was maintained at 4CI+ so that the surface to be painted was uniformly irradiated with ultraviolet rays, and the surface was treated by irradiating ultraviolet rays for 6 minutes in an air atmosphere at approximately 75°C. Ta.

For comparison, an equivalent resin bumper was treated under the same conditions as above using an ultraviolet irradiation device equipped with only a low-pressure mercury lamp.

To paint both bumpers, spray 2-component urethane paint 1 hour after treatment, and immediately apply 80'CX40 paint.
I did some baking.

After baking, the bumper was left in an air atmosphere at room temperature for one day, and the adhesion of the paint film was examined. Cuff the coating film to IC16 width)
A peel test was conducted at 10 locations using a tensile tester, and the adhesion was expressed by the average maximum peel strength. Table 2 shows the processing results.
Shown below. This data is expressed as a relative value when the maximum peel strength of a bumper using both a special ultraviolet fluorescent lamp and a low-pressure mercury lamp as the ultraviolet treatment light source is taken as 100.

Table Also, in order to investigate the variation in adhesion of the coating film due to uneven treatment, the degree of variation in the maximum peel strength was investigated from the results of the Jll test on the coating film side at ten locations. The results are shown in Table 3.

Table 3 From this data, the polypropylene resin bumper was surface-treated using an ultraviolet irradiation surface treatment device that uses both a low-pressure mercury lamp and a special ultraviolet fluorescent lamp as the light source; It was found that the surface treatment effect was significantly higher than that of the bumper, the treatment unevenness was reduced, and sufficient paintability was obtained.

Although one embodiment of the present invention has been described above, the present invention is not limited to the embodiment described above, and various modifications and changes can be made based on the technical idea of the present invention.

For example, a low pressure mercury lamp 15 and a special ultraviolet fluorescent lamp 16
The array configuration of can be changed as necessary.

It goes without saying that the apparatus according to the present invention can also be applied to surface treatment of various resin molded products other than the resin bumper 7.

e. Effects of the Invention As described above, the present invention uses an ultraviolet fluorescent lamp and a low-pressure mercury lamp in combination as a light source, so it is possible to irradiate ultraviolet rays suitable for surface treatment of resin molded products. The surface treatment effect can be enhanced, and the paintability, printability, and adhesion of resin molded products can be improved. In addition, the surface can be efficiently treated at an appropriate illuminance without causing uneven treatment.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of the surface treatment apparatus according to the present invention, Fig. 2 is a characteristic diagram showing the irradiance of a low-pressure mercury lamp and a special ultraviolet fluorescent lamp, and Fig. 3 is a surface diagram of a polypropylene resin bumper for each ultraviolet irradiation wavelength. FIG. 3 is a characteristic diagram showing treated charcoal. DESCRIPTION OF SYMBOLS 1...Surface treatment device, 7...Resin bumper, 15...Low pressure mercury lamp, L...Light source. 3...Processing chamber, 10...Hot air supply mechanism, 16...Special ultraviolet fluorescent lamp, Patent applicant Suzuki Motor Co., Ltd. (and 2 others) Ken Proceedings (Hoshosho (spontaneous)) I. Display of the case 1990 Patent Application No. 21076 2゜Name of the invention Surface treatment device for resin molded products 3゜Name of the person making the amendment (208) Suzuki Motor Co., Ltd. 4 , Agency address university 7-chome, 3-2-3 Akasaka, Minato-ku, Tokyo 107 (2 idiots) 5゜Contents of amendment subject to amendment (1) [Polypropylene... -・-, but" is corrected to "Although the surface treatment wavelength of polypropylene resin is ultraviolet rays of 400 nm or less." (2) Page 8 of the specification, line 13 (7) r400 nm
Correct the value of I to less than r400ns. (3) Specification page 9, line 8 (D lBa5itOs:P
bJ Or Basiz05: Correct to Pb J. that's all

Claims (2)

[Claims] (1) A surface treatment device for resin molded products, comprising a light source that uses a combination of an ultraviolet fluorescent lamp and a low-pressure mercury lamp that emit continuous-spectrum ultraviolet light having a dominant wavelength in the range of 254 to 400 nm. (2) The surface treatment apparatus for resin molded products according to claim (1), wherein the bulb of the ultraviolet fluorescent lamp is made of quartz glass that has good transmittance to ultraviolet rays of 400 nm or less. (3) The ultraviolet fluorescent lamp has a 254 to 400
The resin molded article according to claim (1), which contains one or more types of phosphor that irradiates continuous spectrum ultraviolet light having a dominant wavelength in the nanometer range. Surface treatment equipment.