Polar hot melt adhesive and preparation method thereof

Abstract

The invention relates to the field of adhesives, and discloses a polar hot melt adhesive and a preparation method thereof. The polar hot melt adhesive is prepared from, by weight, 20-60 parts of acrylate segmented copolymer, 20-40 parts of polar plasticizer, 20-40 parts of tackifying resin and 0-20 parts of filler; the acrylate segmented copolymer is a copolymer of styrene and butyl acrylate and / or iso-octyl acrylate prepared by RAFT; all the components are blended and processed into the polar hot melt adhesive. According to the polar hot melt adhesive disclosed by the invention, styrene is used as a hard segment to form a physical crosslinking point, high tensile strength and high-temperature tensile resistance are provided, and butyl acrylate and / or isooctyl acrylate are / is used as a soft segment to provide high elasticity, fatigue resistance and low-temperature flexibility; and the hot melt adhesive with high peel strength, long persistent adhesion performance and good weather resistance to polar materials is obtained under the combined action of a polar plasticizer.

Description

technical field [0001] The invention relates to the field of adhesives, in particular to a polar hot melt adhesive and a preparation method thereof. Background technique [0002] Hot melt adhesive is a kind of thermoplastic adhesive. Its physical state changes with the change of temperature within a certain temperature range. It becomes molten in the heated state and has fluidity. After the temperature drops, it cools and solidifies into a solid state. ability. It has the advantages of fast curing speed, good bonding ability, low volatile organic compounds, etc. It is especially suitable for automation equipment, so it is more and more popular in the market. [0003] In the whole hot-melt adhesive system, the base resin acts as the main component of the hot-melt adhesive, which determines the adhesive force, cohesion and basic properties of the adhesive; additives such as plasticizers and tackifiers can reduce the melt viscosity of the hot-melt adhesive, Improve the wettab...

AI Technical Summary

Problems solved by technology

[0005] 1. Low molecular weight and low dipole moment, so traditional hot melt adhesives have poor cohesive strength and low bonding strength, especially for glass, ceramics, acrylic plastics, metals, ABS plastics and other polar substrates. The knot effect is not good;

[0006] 2. There are many carbon-carbon double bonds in the polymer molecule, so traditional hot melt adhesives have poor heat resistance, anti-aging, yellowing, and UV resistance, and will creep under normal temperature stress; generally heated to 65°C It will soften when it is above 0°C, and most glues will become brittle below 0°C, resulting in a decrease in bonding strength;

[0007] 3. The traditional hot melt adhesive uses non-polar mineral oil, paraffin oil, non-polar mineral wax, etc. as plasticizers, and the polar plasticizer in the bonding substrate will migrate into the traditional hot melt adhesive according to the diffusion theory. Glue, thereby destroying the glued interface, resulting in degumming

[0013] However, traditional acrylic adhesives have the following problems: slow curing speed, low heat resistance, poor cohesive strength, especially at high temperatures

[0021] ①It cannot be prepared into hot-melt pressure-sensitive adhesive;

[0022] ② Due to the presence of carboxyl groups and the effect of hydrogen bonds, the crystallization of the polymer is inhibited, and the linearity of the main chain is destroyed. Although the transparency and toughness of the polymer are improved, the melting point and softening point are reduced, resulting in high and low temperature resistance. not enough;

[0023] ③The polymer material itself is relatively rigid, and the products produced have high strength and stiffness, but at the expense of softness, it is not suitable for soft furniture such as sponges;

[0024] ④The bonding strength is higher than that of EVA hot melt adhesives, but it still cannot meet the market demand

However, the grafting rate is usually not high, so the performance improvement of hot melt adhesives prepared with such polymers is limited, and the cost is greatly increased, which is not suitable for large-scale industrial promotion

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