Ceramic Sugar Pot,Sugar Pot,Porcelain Sugar Bowl Jiabaien Ceramics Co., Ltd. , http://www.czjbeceramics.com
China's carton industry, printing industry, in recent years eliminated the use of silicate alkali water glass as a binder. The plant starch glue is used, and corn starch, sweet potato starch, wheat starch and the like are commonly used as materials for bonding cartons, wine boxes, document bags, and material bags.
Advantages of vegetable starch binders:
1 raw materials cheap source convenient.
2 Natural plants have less environmental pollution.
3 no toxic side effects. 4 Glue processing is quick and easy.
The disadvantages of plant starch binders:
1 Short shelf life, easy to spoil and mold.
2 Plant starch adhesives are easily bitten by rats and infested with insects.
3 The viscosity of the adhesive is poor and the color of the starch gel is poor after drying. The biggest drawback of plant starch adhesives is that they are easily spoiled and have a short shelf life. This problem arises because of the factors in the starch raw material itself, such as the origin and composition of the starch, the nature and content of the additives, and the factors such as formulation and technology, and storage methods.
I. Causes of Insufficient Dehydration of Plant Starch Vegetable starch has a short shelf life and is prone to spoilage and mildew. One of the most important reasons is insufficient gelatinization. Insufficient gelatinization may be caused by two conditions. One is the use of pasting agents. The amount is small; second, the gelatinization temperature is low or the gelatinization time is short, so that the gelatinization of plant starch can not reach a suitable level. Starch, water and pasting agent require uniform stirring. When placed in a pan, the temperature of the bottom layer and the top layer should be the same. If the starch of the plant is degraded during the storage period from 3 days to 6 months, it indicates that the starch is thermally gelatinized and the complexation is insufficient. Therefore, the prepared vegetable starch adhesive may be spoiled and moldy on the 3rd day. The reason for this is that un-gelatinized starch molecules are more susceptible to bacterial attack than gelatinized starch molecules. The gelatinization temperature is high, and the gelatinization reaction proceeds faster. The viscosity of the hot glue in the thermal process glue is not equal to the viscosity of the glue after cooling. Therefore, the viscosity index in the starch glue quality index should not be directly used here to examine the degree of complexation. Because the starch glue after cooling is obviously higher than the viscosity of the hot glue, the hot glue is thinner, the cold glue is thicker, and there is a relatively stable viscosity difference between the cold glue and the hot glue.
Second, the control of good starch glue PH value produced by the plant starch glue PH value> 7 was alkaline, due to the addition of gelatin in the starch, complexing agents are all alkaline substances, if the alkaline plastic starch Too strong, it will make the printed ink on the paper, the carton on the blotting ink, hot stamping electro-aluminum foil gloss drop and discoloration, PH value should be taken to acid and alkali to PH value range to control: PH value of 10 or so.
Third, the plant starch adhesive to defoam treatment
During the production and transportation of vegetable starch, air bubbles are mixed into the plant starch. The bubbles not only affect the use of starch glue, but also promote the deterioration and mildew of the starch adhesive. The reason is very simple, air will cause the starch binder to form oxidation, spoilage, moldy, starch glue is usually butanol, octanol, triphenyl phosphate, etc. as a defoamer, plant starch glue defoamer should be There are dual functions of defoaming and foam suppression, and the defoaming and foam inhibitors used are non-toxic, odorless, and colorless.
Triphenyl phosphate is a solid that is insoluble in water. Since it has a melting point of about 50°C, it can be dispersed in hot water after melting, so it can be uniformly dispersed in the starch glue, so that the glue can be eliminated and suppressed in a timely and effective manner. Bubbles.
IV. Preservatives in vegetable starch
Adding preservatives to the vegetable starch glue is the most effective method for inhibiting spoilage, deterioration, and mildew of the starch glue. Common preservatives include sodium benzoate, etc. The antiseptic effect is better. The amount of sodium benzoate is 0.15% to 0.3% of the total amount of starch glue. Do not add excessive amount of sodium benzoate. The more preservatives are not added, the better the antiseptic effect is. . Sodium benzoate is a safe and non-toxic preservative, and the mechanism of preservation is different from that of fungicides. Therefore, excessive addition of sodium benzoate does not improve its antiseptic effect.
Fifth, plant starch storage and transportation Plant starch glue storage temperature is too high, it will promote the glue liquid spoilage and drying, affect the shelf life. The temperature for storing starch glue is preferably 20°C～25°C. It should be placed in a cool and ventilated place to avoid direct sunlight on the window, so that the temperature can be increased. Place it in a place where the ambient temperature is stable. Packing of vegetable starch glue The container is required to be airtight in the seal, to prevent the container from leaking during the handling, and the starch glue covers the surface of the starch glue in a container with a sheet of paper to prevent its exposure to air oxidation and deterioration, and the storage device is not sealed for a long time. Will cause plant starch glue surface spoilage.
Six, other plant starch glue Some manufacturers in order to prevent rat bites, insects, often add pesticides, 666 powder and other toxic and hazardous chemicals, is very unscientific, is harmful to humans. First, poisonous substances poison the workers in the binding workshop and affect their health. Second, harmful pesticides are added. The smell is unpleasant and affects the use effect. To prevent rat bites, insects, added chemicals must pay attention to safety, and replace with other non-toxic chemicals as well.
Factors for Storage Period of Plant Starch Adhesives
Factors affecting the shelf-life of plant starch binders and their control of adhesives, also known as adhesives, are a class of substances that have excellent adhesion properties and are capable of tightly bonding various materials. The method of using adhesives to connect various materials is called "gluing." The glued material is called "adhered". Organic polymer compounds are more or less sticky and can be used as adhesives. A good adhesive should have a linear structure when in use, a body structure after drying and coagulation so that it can be firmly bonded. The earliest adhesives used by people were mostly adhesive substances derived from nature. Such as animal fish gelatin, bone glue, etc.; vegetable starch, dextrin and so on. In addition to the use of water as a solvent for these binders, the combined ingredients are very simple. In the past 40 years, a large number of synthetic adhesives have been used, such as aldehyde resin adhesives, epoxy resin adhesives, nylon adhesives, and organic glass adhesives.