Fiberglass processing products usually are made of spun textile yarn. Reinforced roving such as winding yarn, the woven roving yarn, pultrusion yarn are rarely used.
The general textile sizing agent:
Paraffin-type sizing agent
The traditional paraffin, vaseline, engine oil, peregal，dye-fixing agent of the sizing agent material have been used for decades, however, many factories has improved the paraffin-type sizing agent.
The important symbol is the addition of a variety of resin film-forming agents in the six basic raw materials of paraffin-type sizing agent to improve the strength and wear resistance of the yarn, such as adding 681,682 water-soluble epoxy, SR-1, SR-2 water-soluble polyester, etc., and adding low degree of polymerization of polyvinyl alcohol such as PVA0488, 0588, polyvinyl acetate emulsion, water-soluble acrylic resin or water-based polyurethane resin, that are very effective methods. KH-550 is often added in the infiltration agent, which can effectively increase the yarn strength and improve the interface with the combination of the interface agent, for different resin system, the KH-570 and KH-560 is also can be used.
The trend of paraffin-type sizing agent is to reduce the amount of paraffin in the formula, some manufacturers use the original 2% paraffin consumption reduced to 0.5%. Even as low as 0.3%, in order to minimize the impact of paraffin on the resin system impregnation.
Using the efficient lubricants. With the development of chemical industry, a variety of efficient sizing agent constantly available, increasing the choice of raw materials. And with the increasing price of the raw material, the profit of sizing agent is decreasing, some dye-fixing factories may replace some of the dicyandiamide with cheap urea, meanwhile, the urea-formaldehyde resin was introduced into the double-amine formaldehyde polycondensate of dye-fixing agent. Although the appearance of dye-fixing agent, viscosity, adhesive force has not changed, but the urea-formaldehyde resin is brittle relatively, resulting in the reducing wear resistance of sizing agent film, and increasing of the broken filament.Many large glass fiber companies use the starch type sizing agent normally, and using the enhanced textile type sizing agents for spun yarn. With the technical development of the glass fiber industry, the market of paraffin sizing agent will become smaller or even disappear.
Starch type sizing agent
This paper discusses how to use starch sizing agent in pot furnace. For tank furnace, there has been a great deal of successful experience in producing textile yarns using starch sizing agents, but for pot furnace of small and medium-sized glass fiber plant, how to successfully use starch sizing agent is a technical problem. Firstly, the starch sizing agent should drawing in insulation environment, and supply oil with a belt oil machine. Secondly, for the technology and equipment, the strand storage and degradation are different with normal paraffin sizing agent. We believe that it is possible to test a large number of glass furnaces with a large number of crucible furnaces (if the scale is too small, it is difficult to control process, and poor in investment efficiency). First, introducing a single-cycle tank with higher precision temperature control, change the oil supply of wheel forging cloth to belt oil machine, and using large yarn winder,
The starch type sizing agent glass yarn with good quality, wide application, easy to heat clean, it’s widely used in the production of printed circuit board yarn. Starch-oil agent has good protective effect on glass fiber, meanwhile the bond strength between yarns is moderate, which is beneficial to puffing. So starch sizing agent is also suitable for producing bulked yarn.
The starch-type sizing agent is widely used in the production of yarns for printed circuit boards. It is of good quality, wide applicability and easy to be cleaned by heat. Starch-oil agent has good protective effect on glass fiber, meanwhile, the bond strength between yarns is moderate, which is favorable for puffing. Therefore, starch-type infiltrating agent is also particularly suitable for producing bulky yarn
Enhanced textile type sizing agent
Enhanced textile-based sizing agents are resin-based, can be divided into the following categories:
Epoxy
The typical sizing agent is NBS-185, is modified epoxy emulsion as the main film former, JF series is based on water-soluble epoxy-based film former. The enhanced textile-based sizing agent often used epoxy emulsion as the main film forming agent, bonding and cluster performance are good, impregnated quickly, and supplemented by efficient imidazoline cationic lubricants, the yarn is smooth and wear-resistant, now NBS-185 sizing agent are used in most plants, the effect is good.
Polyester
Using linear saturated polyester to enhance the textile-based sizing agent film. Polyester-based sizing agent and unsaturated resin, soaking and compatibility is particularly good, with good performance of composite materials, while linear polyester friction coefficient is small, less yarn filament, low cost, so development prospects of the product is good.
Polyvinyl acetate and polyacrylate emulsion
As the large molecular weight, good adhesion, good yarn bundles of film former,it can be used for alkali-resistant mesh cloth, filter cloth and other special occasions, and with extremely excellent performance.
Polyurethane
The 140 series sizing agent belongs to this polyurethane type, the main film former is water-soluble polyurethane resin, with strong adhesive force, the molecular polarity, and it has affinity with most resin, this sizing agent has been widely used. 140 series sizing agent can be divided into 140-1, 140-2, 140-3, 140-4 according to the usage and price.
In addition, the polyurethane emulsion and epoxy, polyester emulsion, also can be used as the main agent of enhance textile sizing agent, the film is tough, wearable, flexible, suitable for high-grade woven glass fiber woven fabric. For the enhanced textile-based sizing agent, strength, wear resistance and penetration rate are the three basic technical performance, for the general resin-based film former, the molecular weight moderate, non-cross-linking type have a good penetration rate, the monofilament strength requirements in terms of good yarn bundles, monofilament uniform force, less broken ends, which requires good lubrication effect of sizing agent, this is because if the lubrication is not good, the friction of yarn on the gathering roll, lubricator, traverse is too large, resulting in the large system tension, when the system tension is greater than the surface tension of the glass droplets, it will broke. Meanwhile, the infiltration agent should be mixed evenly, fine particles (water-soluble is better), so that will form a uniform, dense membrane on the glass fiber surface, and the membrane will protect the yarn on good wear resistance and strength.
The friction coefficient is between 0.8～0.95 without the sizing agent, which is similar with polished smooth steel and brass, after adding good lubricated sizing agent, the friction coefficient will be reduced to 0.2, so it’s a key technology point to select the lubricant of enhanced textile sizing agent, imidazoline, quaternary ammonium salt, long carbon chain polyoxyethylene quaternary ammonium salt and other cationic efficient lubricants are good selections, and these cationic lubricants also have anti-static effect.
The wear resistance of the yarn is also related to the environmental humidity and stress during the retreat, the greater humidity, the greater stress. the less wear-resistant of yarn, and its wear-resisting times are often several times less in the abrasion tester. Therefore, the weaving process to reduce the broken filament considered from the sizing agent, twist structure, environmental humidity and tension. Fabric structure has an impact on the strength of the fabric, the strength of the yarn after the withdrawal of 100%, woven into plain weave, the single yarn strength of 60-75%, woven into plain weave, the single yarn strength of 60-75%, and woven into the forging pattern cloth, the single yarn strength of 70-85%, the retention rate is high.
Enhanced sizing agent
Besides of using the textile sizing agent on most of the spun yarn, enhanced textile sizing agent is also widely used in the deep processing of glass products, enhanced sizing agent is divided into glass fiber reinforced thermosetting resin sizing agent and glass fiber reinforced thermoplastics sizing agent, the examples are as follows:
Enhanced sizing agent for soft yarns
This kind of sizing agents include entangled yarn sizing agent, pultrusion sizing agent and woven roving sizing agent, the epoxy emulsion as main film forming agent system generally. The price of epoxy resin increases a lot till now, polyester emulsion as the main agent of the sizing agent can also get better effect, the bond strength is even better than epoxy, the strand strength is large, however, the problem of the polyester emulsion is that the strand tube and the direct yarn tend to turn yellow when dried. The solution is using bisphenol six system of polyester resin formulations, and control the double bond content of the synthesis formulation,
Formulate the reasonable synthetic process. For the present direct yarn and paired yarn of the new sizing agent, the intensity is more than 0.5N/Tex, the yarn is smooth and wearable, and with fast resin impregnation.
Sizing agent for SMC yarn
The yarn sizing agent is based on cross-linked PVAc as main film forming agent. For the cross-linked PVAc film former, the strength is excellent, tensile strength greater than 25Mpa, the key technology that is using a variety of complex cross-linking agent during the PVAc emulsion polymerization, that is to ensure the necessary cross-linking density does not affect the stability of the emulsion, the SMC yarn of this sizing agent with good cluster, high stiffness, good resin penetration.
Sizing agent for chopped strand mat
The key technology of chopped strand mat yarn is the permeability and transparency of the felt. In addition to the use of instant PVAc in the sizing agent, a certain proportion of polyester emulsion can be used to improve the permeability and transparency of the mat. The polyester emulsion is compatible with the matrix unsaturated polyester resin, the refractive index is very close, there is no fiber trace after the transparent tile was made. After the needed polyester emulsion of the sizing agent forming the film, in addition to ensuring rapid dissolution in styrene, it should have a certain stiffness, toughness, in order to meet the dispersion requirements of the system of yarn-cutting machine group.
Reinforcing sizing agent for thermoplastic
This kind of sizing agents is divided into infiltrating agent for glass fiber filament and infiltrating agent for chopped yarn, which is two kinds of sizing agent with completely different composition. Owing to using one kind of sizing agent without any distinction of the plastic variety, we developed the enhanced PP, enhanced PA, enhanced PET/PBT sizing agent, which is targeted with good interface. The results show that the performance of glass fiber products have reached a high level, especially in the surface quality of products, which with uniform color, non-obvious glass fiber traces.
The key technology of sizing agent is using the high quality film former agents, such as high performance polyurethane emulsions, epoxy emulsion(color is stable under high temperature), dedicated PVAc and acrylic emulsion.
In short, deep processing of fiberglass products is a promising product, its industry is a small investment with quick effect. At the same time, we must vigorously strengthen the research and development of glass fiber infiltration technology, so that the glass deep-processing products in terms of variety or quality to achieve a high level.
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Development of sizing agent for fiberglass products.pdf