Kanglibang problems with silicone and other materials bonding
Because the silicone material with good resistance to high and low temperature performance, can maintain between ℃ to 60 ℃ - 300 good stability, but also has excellent electrical insulation, weather resistance, resistance to ultraviolet ozone, and high permeability, and high transparency, and high tear strength, and good liquidity, easy to processing molding, etc, gradually replacing the rubber and plastic in many applications.
At present, silicone has been widely used in automobile, electronics, construction, daily necessities.
The following to explain to everyone in the production and processing of silica gel products and other materials in the process of bonding to frequently encountered problems.
Generally speaking, with the adhesive effect related to the people, machine, material, method, ring.
Generally the adhesive on the market (also known as: treating agent, interface agent, base coating agent, glue, viscosity enhancer, back adhesive, etc.) is divided into two types of fast drying and slow drying or high temperature bonding and normal temperature bonding.
Quick-drying type is generally silicone primer with instant glue to apply.
It widely used in the silicone adhesive metal (carbon steel, stainless steel, copper, aluminum,and it has a coating of metal silicon (ABS/PC/PVC/PP/PPE/TPU/PPS/PBT/PET/PA/PMMA/PPS/CAB, etc.), silicone adhesive acrylic, silicone adhesive rubber, silicone adhesive ceramic, silicone adhesive bakelite, silicone adhesive material such as fabric.
For silica gel bonding metal, the direct effect can only achieve the bonding solid effect, but can not withstand high requirements, such as factory time resistance to high temperature and high pressure, boiling, salt fog, and uv ozone and other tests.
But for silicone adhesive plastic, there are quite a few models of glue. The most typical is the P+R mobile phone keys.
Are generally using silicone adhesive PC/ABA/PC and BAS/TPU material mixture, first started in this field is South Korea locate 770 series treating agent is developed, with instant glue good solves the silica gel and plastic adhesive can't give such as resistance to high temperature and high pressure water salt fog test (test the length of time is relative, the original mobile phone do better).
Silicone bonded silica gel also has the above problems.
In addition, it is necessary to explain that no matter it is metal bonded by silica gel, plastic bonded by silica gel, silica gel bonded by silica gel or silica gel bonded material, the phenomenon of hardening and whitening will occur.
Hardening refers to the silica gel and the adhesive surface of the silica gel lost more flexibility and toughness, become hard, just the degree of different hardening glue is not the same.
The whiteness is specific to the treatment agent.
Therefore, we need to choose our own treating agent and quick-drying glue according to the requirements of the production.
Another is silicon and other materials bonded after hot during molding.
That is to say, when forming silica gel bonding metal/plastic/silica gel, after applying the glue after heating, so that the glue quickly curing.
The temperature of heating varies according to the glue, the curing time is also different, and the bonding effect is also different.
On the market, some products need to be heated to prevent the glue from curing for a period of time (usually 12 hours to maximize the bonding effect), while others need to be heated to quickly cure the glue and achieve the highest bonding effect.
Kl-301a /B is developed by concord technology co., ltd. has such characteristics, and there is absolutely no smell out.
For some products with high requirements (such as high temperature, high pressure and ultraviolet ozone resistance, etc.), it can quickly achieve the effect of mass production, avoiding many inconveniences brought by the slow drying process, such as rebound, dislocation and eliminating large area of production site, etc., which can effectively reduce the production cost of customers.
Another aspect is the silica gel and other materials not curing molding, widely used in silicone bonding metal, ABS/PC, nylon, epoxy resin, bakelite and other hard substrate.
Silica gel bonding metal recommended to use high temperature vulcanizing agent (double 25), vulcanizing temperature between 170℃-190℃, the rate of vulcanization is faster, compared to the low temperature vulcanizing agent (platinum vulcanizing agent, double two tetrahalide agent) can be in the same time to mold more, can save the cost.
In the process of hot bonding of silica gel and metal, there is often the problem of unstable bonding: the main reasons for this problem are: 1, the metal surface is not treated clean, generally can use toluene or methyl ketone to clean, decontamination ability is better.
2. Silica gel is not coated evenly or repeatedly, which affects the bonding effect.
Evenly brush the glue on the surface to be bonded, or soak the parts in the glue, or spray the glue evenly on the surface to be bonded.
3, dry: this is the key, are generally used at room temperature drying and heating drying method.
Normal temperature drying generally takes a long time, production needs to be put into operation in advance, according to the nature of the product is different, the drying time is different.
The method of baking is more in line with most of the products, heating can be faster is the water in the glue out, and can make the adhesive to maintain the temperature, improve the molecular activity of the treated metal surface, can play a better bonding effect.
4. Finally, silicon rubber and metal are put into the mold for molding.
5. Special attention should be paid to the fact that after applying the glue, do not place it in the dusty place during the drying process, and try to avoid the contact between the hands of employees and the surface to be bonded during the whole operation, because the sweat on the hands will have a great impact on the bonding effect.
If contact is not avoided, leather gloves or finger covers are recommended.
Silicone hot bonding plastic, most of the products are silicone bonded nylon, silicone bonded PC, silicone bonded ABS.
Silica gel bonded nylon is generally used double 25 high temperature vulcanization, to speed up the production speed, silica gel and PC and ABS hot bonding must use platinum vulcanization agent, low temperature vulcanization, curing temperature control in 150℃ and 110℃ below (to see how much plastic can withstand temperature deformation), other operating methods and adhere to the metal is basically the same.
But here there is a need to pay special attention to: that is, when dry to pay special attention to, because the plastic has the characteristics of water absorption, if you do not dry the processing of the adhesive effect is particularly large, especially prone to bubble adhesion, bonding, spots and other conditions.
Therefore, the general plastic materials bought in the sun to insolate for a period of time, or in the warehouse storage of the time to take out in the oven for a period of time to dehumidify and remove impurities (some impurities will be released when heating, adhesive is also affected).
Finally, the black adhesive (silicone adhesive, double-sided adhesive, 3M adhesive).
Silicone and double-sided adhesive widely used in the silicone rubber pad and seal ring, can play a good role in anti-slip shock and seal.
But the process of bonding is often encountered in the case of weak bonding.
This situation generally occurs from: 1.
2. Whether the glue brush is evenly applied;
3. Whether the glue is dry;
4. Whether the adhesive paper is 3M adhesive or not;
5. Silica gel raw materials, etc.
KANGLIBANG is to creat solution for your problem with bonding silicone, welcome customer inquiry to us.