JPH0357143B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a modified synthetic resin molded product whose surface is subjected to pulse irradiation treatment with an excimer laser, and particularly to a polytetrafluoroethylene or polyimide resin molded product that has significantly improved adhesion, printability, and paintability. The purpose is to provide. Synthetic resin molded products, such as films and sheets, may be used as they were when molded without any printing, painting, or other secondary processing; Alternatively, it is often used by adhesively compounding or laminating it with different types of resin molded products, metals, glass, and other inorganic materials. However, in these cases, the surface of the synthetic resin molded product has poor affinity with printing inks and paints, making it impossible to print or paint using conventional methods, or due to poor adhesion, it is difficult to use composite products. Quality performance is often compromised,
Improvements in surface adhesion, printability, and paintability are strongly desired. Conventionally, methods for modifying the surface properties (adhesion, printability, paintability, etc.) of synthetic resin molded products include acid and
Wet treatments such as alkal treatment, primer coating treatment, corona treatment, etc. are used, but wet treatment methods such as acid/alkali treatment are not welcomed due to the use of powerful chemicals and waste liquid treatment, and primer treatment is This has the disadvantage of increasing the extra steps of coating and drying. Moreover, corona treatment has a poor durability of effect, and the adhesiveness and printability imparted to it disappear over time, and the modification effect itself is low, especially when C-X bonds (X is a halogen) or C-N There is a drawback that the modification effect on synthetic resin molded products having bonds is small. On the other hand, as a recent technology, a modification method has been proposed in which the surface of a synthetic resin molded product is treated with low-temperature plasma using glow discharge in a reduced-pressure gas atmosphere, which improves surface properties such as adhesion and printability. Effects can be obtained. However, in order to carry out this method on an industrial scale, there is a drawback that very large and expensive equipment is required. Modification methods using short-wavelength ultraviolet light treatment are also being considered, and are expected to be effective for polyolefins, polyesters, etc.; In the case of synthetic resin molded articles having the above-mentioned properties, the effect of surface modification cannot be expected. The reason for this is not clear, but normally, for short wavelength ultraviolet light treatment, a discharge tube or lamp with a suitable window material filled with a gas that generates an emission line or continuous light of 255 nm or less is used as a light source. The irradiation light is bright line or continuous light of various wavelengths, and includes light of wavelengths unnecessary for modification that improves properties such as adhesion, printability, and paintability of the surface of the molded product, and it causes the modification reaction. It is presumed that this is inhibiting the Recently, excimer laser oscillation has been confirmed, which utilizes an excimer created by the bond between an excited state atom (molecule) and a ground state atom (molecule), and is attracting attention as a new photochemical reaction light source. The inventors particularly focused on the monochromaticity (single wavelength light) of lasers, which cannot be obtained with conventional discharge tubes and lamp light sources, and applied this to the adhesion and printing of molded products made from polytetrafluoroethylene or polyimide. As a result of considering its use in a surface modification reaction aimed at improving paintability and paintability, the surface of the molded product was treated with short pulse irradiation with an excimer laser in the wavelength range of 95 to 200 nm to improve adhesion to the surface layer of the molded product. The present invention was completed by discovering that an extremely thin modified layer that significantly improves printability and paintability can be formed without any deterioration of the mechanical properties of the molded product itself. The present invention will be explained in detail below. The polytetrafluoroethylene or polyimide used in the present invention is not particularly limited in terms of its molecular structure, molecular weight, etc.;
It may be a copolymer, a block copolymer, a graft copolymer, a mixture of different synthetic resins, or the like. In obtaining molded products from these synthetic resins,
Various compounding agents, additives, or processing aids may be added, such as plasticizers, stabilizers, lubricants, fillers, extenders, pigments, dyes, heat resistance improvers, flame retardants, and antiseptics. Even if an oxidizing agent, a weathering agent, a light absorbing agent, a surfactant, a crosslinking agent, an antifogging agent, a moisture proofing agent, an elasticity improver, etc. are added and blended, the effects of the present invention are not affected. The present invention targets films, sheets, and other molded products of various shapes, including the casting method,
It is manufactured by conventionally known molding methods such as melt extrusion, calendering, stretching, and compression. The surface of the molded product obtained in this way is
Pulsed irradiation is performed using an excimer laser in the 200 nm wavelength range, and for example,
Ar2 (126nm), Kr2 (146nm), Xe2 (172nm),
Examples include ArCl (175nm), ArF (193nm), etc.
It is also possible to use these harmonics, and it is also possible to use them after wavelength conversion using a Raman shifter. Laser beams with wavelengths over 200 nm only have the effect of photodegrading and thermally degrading synthetic resin molded products, and laser beams with wavelengths of 95 nm or less are not yet known, but they are presumed to be quite large and expensive, and this book Not suitable for the purpose of the invention. The excimer laser pulse irradiation treatment performed on the surface of the molded product can be performed under the conditions of an average output of several watts to several tens of watts, a repetition frequency of 1 Hz to 100 Hz, and a pulse width of 14 nsec or less, thereby creating a thickness on the surface of the molded product. An extremely thin modified layer of 1 μm or less is formed, resulting in curing that significantly improves adhesion, printability, and paintability. In addition,
Since the modified layer is extremely thin, the inherent mechanical strength and other physical properties of the molded article are not impaired in any way. Next, specific examples will be given. Example 1 Polytetrafluoroethylene sheet (Daikin
TFE-Polyflon, manufactured by Co., Ltd.) and polyimide film (Kabton, manufactured by DuPont Co., Ltd.) were prepared, and their surfaces were irradiated with 30 pulses using an ArF (wavelength 193 nm) laser under conditions of pulse energy 100 mJ and pulse width 10 nsec. (equivalent to processing at 10Hz for 3 seconds). Each of the sheets and films treated in this way was divided into two parts, and the treated surfaces of each were glued together using an epoxy adhesive (Bond E-Clear Set, manufactured by Konishi Co., Ltd.), and after curing at room temperature for 48 hours, T-peel strength was measured. At the same time, the contact angle of water on the treated sheet and film surfaces was measured to evaluate hydrophilicity. In addition, printing ink (GRP ink manufactured by Toyo Ink Co., Ltd.) was used to evaluate printability and paintability.
was applied to the treated surface and allowed to dry at room temperature for 72 hours, then a cellophane adhesive tape was sufficiently applied to the coated surface and immediately peeled off to examine the adhesion of the printing ink. The results were as shown in Table 1.

[Table] Untreated: Without UV laser treatment
Treatment: Case with ultraviolet laser treatment Example 2 ArCl (175n
m) Using a laser, pulse energy 100mJ,
20 pulses irradiated (10Hz2) under the condition of pulse width 14nsec.
(equivalent to 2 seconds processing) was performed. The sheets and films subjected to laser surface modification in this manner were subjected to T-peel strength, water adhesion angle, and printing ink peeling tests in the same manner as in Example 1 to examine the modification characteristics. The results were as shown in Table 2.

【table】

Claims (1)

[Claims] 1. A surface-modified synthetic resin molded product obtained by pulse irradiation treatment of the surface of a molded product made from polytetrafluoroethylene or polyimide with an excimer laser having a wavelength range of 95 to 200 nm.