Hot melt pressure sensitive adhesive is a kind of pressure sensitive adhesive, mainly composed of synthetic rubber, resin and rubber oil mixed into a melting state, and then coated in cotton paper, non-woven fabric or plastic film and other substrates and made of a new adhesive tape.

（Multi function medical tape coating machine）

Low cost is its biggest advantage, the disadvantage is that the viscosity affected by temperature is obvious.Mainly used for all kinds of sealing box, sealing box, paper packaging, beverage bottle label, sealing aluminum foil, flexible packaging and other packaging and environmental protection paper pallet, suitable for all kinds of materials.

Medical hot melt pressure sensitive adhesive is a classification of medical hot melt adhesive, widely used in the processing of medical tape, infusion paste, band-aid and other medical and health products. Medical hot melt pressure sensitive adhesive has both hot melt and pressure sensitive. In the process of making adhesive products, it should be heated and melted by special equipment, which reflects hot melt. The adhesive products, such as medical tape and band-aid, can be glued by finger pressure after being torn, which reflects pressure sensitivity.

Requirements and standards for medical hot melt pressure sensitive adhesives

When medical hot melt pressure-sensitive adhesive is used in medical products such as medical tape, elastic bandage, wound paste and surgical incision film, various problems arising from contact with skin must be considered, which are described as follows:

1, hypoallergenic

The medical hot-melt pressure-sensitive adhesive products in use require no irritation to the skin, such as redness, itching, small papules and other allergic reactions.

2. Air permeability

Hot melt pressure sensitive adhesive products have good breathable performance, it will greatly reduce the skin allergy, and make the skin covered by adhesive products as usual breathable breathing, for the skin sweat, keep the wound dry, accelerate the wound healing has a positive effect.

4. Adhesion

Human skin can be dry or oily, hairy or hairless, smooth or rough. Medical hot melt pressure sensitive adhesive products can meet the needs of most people's skin, paste on the skin, can be in a humid or stuffy environment, skin sweat, body fluid secretion condition, still maintain a certain adhesive force, does not produce warped and quickly fall off the phenomenon.

4. Compatibility with skin

(1) Peeling strength should not be too large: the peeling strength of the medical hot melt pressure-sensitive adhesive products of the paste skin should not be too large, and should be kept within a certain limit, otherwise the skin will have a feeling of tightness and discomfort. When it is removed, there is a sense of pain and it is easy to pull up the hair and damage the skin.

② The initial viscosity of the skin is better: because the material is mostly used in the wound or around the wound, it should not be squeezed hard, so the initial viscosity of the rubber products is better, and the instant can stick to the skin.

(3) No residual glue after tearing: no residual glue remains after tearing from the skin, especially around the edge of the adhesive material.

Five. Adaptation to disinfection treatment Many adhesive stickers applied to wounds and wound stickers need to be disinfected, and adhesive products can not be deteriorated because of disinfectant. At present, gamma-ray and drill ray disinfection has little effect on glue, while hot steam disinfection can be used

Can cause change.

Medical tests must be carried out

(1) Cytotoxicity test: check the possible existence of precipitated toxic substances in the adhesive.

(2) Skin irritation test: It is used to test whether there is possibility of skin irritation caused by precipitates in the material after gluing.

(3) Skin allergy test: Repeat the trial in different age groups and different people to test the skin allergy reaction.

Gluing method

There are many ways of gluing hot melt adhesive. No matter which way of gluing, hot melt adhesive must be pre-heated into a molten state in the melt groove, and then directly sprayed or transferred to the substrate or the adhesive with appropriate gluing equipment. Common medical tape substrate with non-woven fabric, PE film and silk cloth. There are two types of glue equipment: roller and die head.

characteristic

Hot melt pressure sensitive adhesive applied in the market of medical tape, in addition to appropriate coating operability and heat stability, but also need to have the characteristics of non-itching, adhesive and breathable.

(1) Coating operability

As described in the previous section, hot melt pressure sensitive adhesive can be applied to various special substrates with special die heads or rollers. However, the hot melt pressure sensitive adhesive used for medical tape usually has high fluidity, which is easy to penetrate into the porous substrate and cause the overflow phenomenon. In addition, the substrate used in many medical tapes cannot withstand high heat and can be extended, deformed or even destroyed when glued. As a result of these operational difficulties, hot melt pressure-sensitive adhesive is usually applied to heat-resistant release paper and then transferred to various substrates.

② It does not itch.

The solvent-based glue commonly used on medical tape can cause skin irritation. Zinc oxide powder should be added to the glue. The function of zinc oxide powder has two aspects: one is to reduce the skin allergy of solvent-based glue; The second is to improve the hygroscopicity of the glue or the ability to absorb sweat.

(3) adhesion

Since natural viscosifying resins such as rosin or rosin are not suitable for medical tape, it is necessary to rely on the softness and wettability of hot-melt pressure-sensitive adhesive itself, namely the so-called viscoelasticity. In the design of hot-melt pressure-sensitive adhesive for medical tape, special attention should be paid to the fluidity of human skin. After the tape is applied to the skin, it must have the ability to continuously moisten and stay close to the skin surface. Ideally, the tape should not warped off due to the bending motion of the joint.

(4) Permeability

In order to prevent irritation to the skin, the hot melt pressure sensitive adhesive used for medical tape is usually composed of no polar substances (hydrophobic polymers). Because it doesn't absorb moisture and expel sweat. If you want to get proper air permeability, can be in the back glue, tape base material together with glue to take appropriate interval drilling. Or can use special coating processing equipment to cause a non-full version, coated surface to form air holes. Both of these methods allow medical tape to achieve some degree of air permeability.

⑤ Other physical properties

The adhesive object of medical tape is human skin. No matter at any time and space, the surface temperature of human skin is about 30-35℃. Therefore, in addition to the storage and transportation period should pay attention to whether the hot melt pressure sensitive adhesive will be caused by excessive liquidity phenomenon, in general, medical tape with hot melt pressure sensitive adhesive unlike other purposes of tape and labels need to pay special attention to heat resistance and cold resistance. However, each person's skin is dry, oil properties are different, but users will feel different degrees of adhesion and adhesive force.

conclusion

Driven by the progress of science and technology and the continuous pursuit of improving the quality of life, the products of the medical system have been constantly improved and innovated in recent years. Medical compresses, patches, and tapes, regardless of their function, must be combined with appropriate adhesives in order to secure these applications to the skin. Because most hot melt pressure sensitive adhesive must be manufactured and coated at high temperature (170-180℃). Therefore, it is not suitable for the addition of drugs with volatile low boiling point or sublimation point.

At present, solvent adhesive, water adhesive and hot melt adhesive coexist in the medical system products, in addition to the different operation, indeed each has its special function. However, it is undeniable that the hypoallergenicity of hot melt pressure-sensitive glue and the breathable characteristics obtained after processing are incomparable to other types of glue. From the perspective of environmental protection, zero pollution hot melt pressure sensitive adhesive should be the inevitable direction of development in the future.