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Author: Li Zhiyun Pang rahaeng
unit: Guangdong Boxing new Mstar Technology Ltd
the organosilicon material has very low surface tension the (19.1mN/m), can significantly reduce the interfacial bonding strength, compared with the organic fluorine material has a large cost advantage, so it is often used as coating materials from.
type paper at home and abroad from the type of paper used for curing silicone coating materials are heat cured and UV curing 2. Compared with UV for curing heat curable silicone resin material, but cheap.The commonly used solvent system. High curing temperature. High energy consumption. The efficiency is low, for many substrates at high temperature baking process to.
UV curing technology with its powerful energy. Environmental protection. Dominant global rapid development, greatly reduced. Coating printing. Bonding field VOC emission and energy consumption in building materials. Electronic. Photoelectric. Application of packaging and printing fields, has produced great economic and social benefits. The UV curing silicone products are divided into the curing mechanism of cationic and free radical, while the cationic resin curing shrinkage. Strong adhesion. Anaerobic polymerization, but the system is not stable (cationic coating by the moisture of the environment large) Limited the large, so the current market most of the UV free radical curing process of.
from the coating (isolation coating) is a kind of prepreg to prevent adhesion and anti sticking coating to protect prepreg from pollution. Compared with the conventional UV resins, silicone acrylate resin and its oligomers due to greater oxygen absorption and penetration (poly two methyl siloxane oxygen diffusion coefficient is 605 * 10-10cm/s however, PMMA is only 0.154 * 10-10cm/s), so the current implementation of UV key technology of silicone acrylate from the type of paper products is the removal of oxygen in the system, such as the pre purge, for very thin coatings (< 10 m) is a kind of fast on the substrate surface to form a seal to the effective absorption method and the oxygen diffusion barrier. But if the nitrogen purge protection, the inevitable need to upgrade the original coating equipment, increase the nitrogen or nitrogen storage equipmentEquipment, increase the cost of
coating; so this paper attempts without nitrogen protection under the effect of UV in curing silicone resin coating by research group. Monomer prepolymer. Effect of additives and coating on the basic properties of the coating, resin preparation and suitable low peel strength silicone good adhesion from type.
1 coating part 1.1: the main raw material of
UV resin: B-530 polyester acrylic resin.B-619 functionality acrylic resin, self-made; UV curing silicone resin: OS1, OS2 self; UV monomer: Double pentaerythritol six acrylates (DPHA), three hydroxy three propane acrylate (TMPTA), pentaerythritol three acrylates (PE - TA) industrial grade, Taiwan, Changxin; catalyst: 5% chloroplatinic acid isopropyl alcohol solution. Two lauric acid two Ding JiTin, Leon, reagent; inhibitor: 2,6 Di tert butyl phenol, Leon, reagent; additives: BYK346 (wetting leveling agent); photoinitiator: 1173, TPO-L, 819, BASF; solvent: butyl acetate. Two butyl ketone, industrial grade; isophorone diisocyanate (IPDI): Wanhua. Reagent; hydrogen containing silicone oil, industrial grade.
1.2 main equipment
high speed dispersion machine; pencil hardness; DF-101S heat type constant temperature heating stirrer, Gongyi Yuhua; UVAD301-36 crawler type UV curing machine, Shenzhen runwing mechanical.
1.3 style preparation
and performance test of
1.3.1 coating in accordance with certain mass ratio the organic modification of acrylate and acrylateSilicon, initiator. The leveling agent, sealing and then put into the 70 DEG C oven, stirring, mixing static bubble removal using the.
coating, surface coating coating with the wiper on ABS, a crawler type UV curing machine on UV curing. Spraying, configuration good paint solvent for dilution, in gun drencher cabinets surface coated ABS plate, placed in the temperature of 70 DEG 5min oven, performance of UV curing coating.
hardness test using pencil hardness test method; adhesion tests: coating adhesion test according to GB9286 - 1988; peel strength test: peel strength is one of the evaluation the main index of chemiacal performance, this paper adopts 3M tape or VOID film to release coating from the type of force testing.The price of.
1.3.4 infrared spectroscopy of
NicoletIS5 infrared spectrometer were determined. The frequency of 400~4000cm-1, with KBr as substrate, powder samples using mixed grinding compression method, liquid samples coated with membrane were tested by KBr
1.4UV tablet as a synthetic blank curing silicone resin for free radical curable silicone resin, there are 2 synthesis methods. One is adding through silicon hydrogen directly using acrylate monomers and silicone oil containing hydrogen addition reaction, light cured silicone molding, as shown in Figure 1; another is through the reaction of terminal hydroxyl silicone oil as carbon hydroxyl of carbamate, using hydroxyl acrylate compound end capped polyurethane.A Xie Yin clima convex Bi way:?
1.4.1UV cured silicone resin OS1 first adding hydrogen containing silicone oil and acrylate monomers in the flask (Si-H: single =1: 1), stirred and adding amount of inhibitor, is heated to 120 DEG C, adding catalyst, using infrared by monitoring the reaction until the reaction is complete conversion, termination and discharge, avoiding the synthesis of
light cured silicone resin OS2.
1.4.2UV and preserved in adding hydroxyl silicone oil in a flask, opening stirring, adding proper amount of inhibitor, is heated to 45 DEG C, adding catalyst and adding a certain amount of IPDI, reaction time test the conversion rate of NCO, adding hydroxyl acrylate compounds, to a period of reaction? by infrared chromatographic monitoring reaction until the reaction is complete conversion, termination and discharge, the synthesis conditions of
reaction save spare.
2 results and discussion
2.1UV curable silicone resin: temperature 120, Si - H: =1 monomer: 1 catalysts: 5 * 10-5Pt; the relative molecular weight of 1000 and 2000. Hydrogen containing silicone oil respectively with TMPTA and DPHA based on the preparation of UV addition cured silicone resin OS1 series oligomer synthesis data are shown in Table 1.
can be seen from table 1 using silicon hydrogen, hydrogen containing silicone oil and acrylate compound addition reaction rate, using infrared detection, reaction conversion rate can reach more than 98% in the 2.5h DPHA, reactive functionality higher and higher, the molecular weight of silicone oilThe amount had no obvious effect on the reaction; because the relative molecular weight of 1000 and 2000 of the silicone oil viscosity had little difference, so little difference after addition of the corresponding viscosity oligomers; but the addition product viscosity compared with the viscosity of silicone oil containing hydrogen, bigger, liquidity, which may be caused by hydrosilylation reaction chain extension reaction part and product internal polar groups increased. Figure 3 is the initial stage of the reaction and infrared spectra of silicon hydrogen 2.5h,
can be seen from Figure 3, 2924.7cm-1 and 2848.6cm-1 are CH2 anti symmetric and symmetric stretching vibration peak at 1730.4cm-1 is C==O stretching vibration peak. At 1635.5cm-1 - CH==CH2 bending vibration peak, at 1473.6cm-1 - CH2 - bending vibration peak; at 1010~1115cm-1 Si O stretching vibrationDynamic peak; in 2130cm-1 (Si - H) absorption peak completely disappeared, proved that the reaction completely.
relative molecular mass of 2000 hydroxy silicone oil based on isocyanate addition reaction with pentaerythritol three acrylate terminated, UV curing light curing
2.2UV silicone resin cured silicone resin to evaluate the basic properties of light the synthesis of the UV curing curing silicone resin, table 2 shows the initiator system using different silicone acrylate oligomer, because of oxygen greater absorption and penetration, UV curing effect by oligomer oxygen inhibition significantly, and when coated with the curing of coating, curing oligomers good, direct inhibition of oxygen inhibition of the polymerization. And even functionalityThe lower polyurethane silicone OS2-1 UV curing, oxygen inhibition effect is not obvious; this may be due to the relatively low silicone content in polyurethane, on the other hand, polyurethane polymer viscosity is larger and the oxygen permeation ability is poor, to a certain extent reduces the oxygen inhibition by 3M tape. To test the coating after curing, although OS2-1 curing is better, but the peeling force and OS1 series; test the peel strength is obviously much lower. Two kinds of silicone resin from huge difference type performance, mainly due to polyurethane silicone resin containing more carbamate polar functional groups. Easy to form strong interaction with pressure sensitive adhesive. Therefore, in order to realize the application of silicone resin in coatings from the in air atmosphere, need to further adjust the coating based on OS1These awards to achieve low Na soil? Peel force coating preparation.
2.3 light curing type formula for preparation of
Table 2 based on the experimental results, the larger molecular weight of silicone oil, with UV light curing formula in air environment as shown in Table 3 for UV curing silicone resin OS1-4 functionality is higher. The formula 1 and 2 the surface of the coating is still difficult to achieve complete cure, there is still some sticky hands; but the formula 2 is better than that of Formula 1, this is due to a high level of B-619 resin resulted in the formula; in order to maximize the retention of silicone composition, part of the OS1-4 in the formula are replaced by OS2-1 the results found, curing formula of 4,5,6 curing, in good condition, with 3M adhesive tape stripping experiments, a low stress,Formula 4 and 5 the peel force difference formula 6; peeling force is large, probably due to B-530 functionality is low, can not form a dense coating caused by; through the explain of oxygen sensitive UV curable silicone resin can be regulated through the formula to overcome oxygen inhibition in order to obtain, with light curing coating some from the properties of the coating surface can be adjusted by adjusting resin stripping force (off force).
of hydrosilylation synthesis of light cured silicone material, characteristics of the silicone surface free energy based on the lower of the free radical curing silicone material in the application from the type of paint and obtain the better performance of the silicone release coating. In addition, UV curable polyurethane silicone with high wear. High hardness.The characteristics of resistance to chemicals, along with synthesis technology to the enrichment and development of UV silicone resin curing cost reduced, application will also continue to expand.
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