The 135°C high temperature resistant composite film is mainly used in the manufacture of high temperature cooking bags. The high temperature steaming bag was developed in the United States in the 1960s and used for astronauts food packaging. It is placed at room temperature for long life. When it is eaten, it can be eaten cold and can be hot food. It is convenient to use and saves saved energy. Therefore, it is very popular among people. In 1964, Japan's Otsuka Food Co., Ltd. succeeded in using high-temperature cooking bags (transparent) to package curry foods. In 1970, Japan sold 70 million high-temperature cooking bags, but sold 100 million in 1971. Until now, sales of high-temperature cooking bags have continued to grow at an annual rate of 15%.
The features of the high-temperature cooking bag are as follows: 1 It can kill all bacteria, and it has a long shelf life. The transparent image has a pot life of 1 year or more. The opaque aluminum foil (middle layer) bag has a shelf life of 2 years or more; 2 Oxygen permeability and transparency Very low wetness, no spoilage of the contents; 3 Can use canned food production technology and equipment, so the high-temperature cooking bag is also called soft cans; 4 sealing is reliable, easy to operate; 5 bags leave a crack, easy to open, with hand One tear or unsealing; 6 decoration printing beautiful; 7 can be heated within 3min; 8 waste is easy to handle; 9 can be stored at room temperature.
Usually, all pathogenic bacteria will be killed at a temperature of 85°C, but botulinum and spore bacteria with a high risk of toxicity will be killed at 135°C for 10 minutes. Therefore, it is required to forge polyurethane adhesives for composite films. Resistant to 135 °C.
Example 1: (Main agent: Poly terephthalic acid - isophthalic acid - azelaic acid - ethylene glycol - epoxy resin)
Dimethyl terephthalate (194.2 g), ethylene glycol (248.3 g), and zinc acetate (0.2 g) were used to pass nitrogen through the transesterification reaction at 160-220°C. After methanol was distilled off, 83.1 g of isophthalic acid was added. The esterification reaction was carried out at 200-220°C, and the water formed by the reaction was distilled off. Then, 282.3 g of sebacic acid was added and the esterification reaction was carried out at 220-230°C. The pressure was gradually reduced and the mixture was condensed at 220-230°C for 60 minutes and then reduced. Pressing to 133 Pa and condensing at 220-230°C for 4 hours produced a polyester polyol having a number average molecular weight of 50,000.
The polyester polyol obtained above was dissolved in 67 g of ethyl acetate, 2 g of phthalic anhydride, 0.1 g of phosphoric acid, and 15 g of epoxy resin (Epikote 1002) were added, and the mixture was heated and stirred at 60° C. for 4 hours to obtain a solid content of 50%. Thick liquid (main agent).
The curing agent was an IPDI trimer containing NCO% of 17.3% and was formulated with ethyl acetate to a solution with a solids content of 50%.
According to the main agent: curing agent = 100: 7.5 (parts by mass) formulated into an adhesive.
The composite film was structured as a polyester film (12/um)/adhesive/aluminum foil (9um)/adhesive/unstretched polypropylene (70um), and the bonded film was cured at 50°C for 3 days. Cut the composite film
The test piece with a size of 360mm*l5mm was tested on a peeling machine and the peel strength between the aluminum foil and the unstretched polypropylene film was 1250 g/15mm.
The composite film was made into a food bag of 13cm*l7cm in size, and contained vinegar with a concentration of 4.2%. After being sterilized by hot water at 135°C*30min and 0.45 MPa pressure, the composite film was stored at 60°C for 7 days. Separation phenomenon. After the heat and acid resistance test, the peel strength of aluminum foil and polypropylene film was 1000g/15mm.
In the adhesive component, a 1% Y-glycidoxypropyltrimethoxysilane (KH-560) coupling agent is added, which is superior in heat and hydrolysis resistance.
6. Solvent-free composite film adhesive
Domestic and international attention to environmental pollution is very important. The use of solvent-free polyurethane adhesives for composite films can completely solve the problem of solvent-induced pollution. In 1974, German company Henbet first used a solvent-free polyurethane adhesive to make composite packaging materials. In the United States, the solventless adhesive accounted for 10% in 1977, and it accounted for 50% in 1980 and is expected to account for more than 90% in the 1990s. In China, solventless coater equipment has not been popularized, so the use of solvent-free polyurethane adhesives is less. In the future, solvent-free polyurethane adhesives will have a wide range of development prospects.
1. Coating process
Solvent-free polyurethane adhesives are available in two-component and one-component types. The two-component type has a higher viscosity at the room temperature and a curing agent but still has fluidity and is a semi-solid substance. When compounding is required, the main agent and curing agent are mixed in proportion, placed in a plastic disk with a heat-retaining function, and heated to 50-60° C. to reduce the viscosity to 1 Pa·s or lower, and then passed through with heat insulation. A functional gravure roll is applied to the substrate. After being glued, it is not necessary to heat and dry it through a drying tunnel, because it does not contain any solvent itself and can be directly compounded with another substrate.
The use of solvent-free adhesives eliminates the need for emissions, eliminates the need for large and complex heating blasts and exhaust gas treatment devices, and offers simple equipment, raw material savings, reduced energy consumption, low maintenance costs, and increased production speeds, resulting in significant benefits. At present, most common composite film packaging materials can be produced with solvent-free adhesives, and even high-grade composite film packaging materials resistant to high temperature cooking at 121° C. can be manufactured by this method.
2. Features
1 The environment will not cause pollution due to solvent evaporation, safe operation, no explosion-proof measures; 2 glue coating amount 0.8-2.0g/m2 (usually 1.0g/m2), only half of the solvent type; 3 composite The process is simple, the composite speed is high, and the energy consumption is saved. 4 Because the process of heating and drying the solvent is not required, the coater equipment is simple, compact, economical, and the floor space of the plant is small; 5 there is no problem of contamination of the food caused by solvent residues and migration; 6 The operating temperature is lower than that of the solvent type, which will not cause deformation of the film at high temperature; 7 The viscosity is large, and it needs to be preheated during use. Generally, the viscosity at the time of coating is 1000 to 3000 mPa·s; and the viscosity at room temperature is 4000 mPa·s. When the two components are mixed together, the viscosity can reach 23 mPa·s within 1 h, so the pot life of the two-component solvent-free adhesive is short, only 1 h.
Comparison of composite membranes prepared with solventless polyurethane adhesives and other composite membranes is shown in the following table. Comparison of solvent-free composite membranes and other composite membranes
Compound method Coating weight, g/m2 Speed, m/min Heat-resistant water and oil resistance Transparency Curl residual solvent Solvent-free compound 0.8-2.0 100-200 Youyou Youyou compound 5-15 80-150 Excellent good-good heat Melt composite 4-10 100-150 Poor excellent extrusion composite 0.1-1.0 80-180 Liangliang poor good
Wet compound 4-10 70-150 good poor poor
For the meat marinating solution we refer to meat tenderizer, Saline mixer, Saline injector(brine injection systems), vacuum massage tumbler.
Saline injector can evenly inject the brine and salt auxiliary materials into the meat blocks, which can shorten the pickling time and greatly enhance the taste and yield of the meat products. The machine can be adjusted with stepping rate, stepping distance, injecting interval and injection pressure according to the technological requirements. Then the brine and salt auxiliary materials can be injected into the meat evenly and continually to reach the optimal effects.
While vacuum tumbler makes meat rolled in the drum under vacuum condition, similar to pulmonary respiration (make product to inflation and shrink alternatively). It makes meat salted evenly, increases the adhesive quality and taste and ensures the freshness of meat.
Injector series:multi needle injector,brine injector,poultry meat injector,fish injector,red meat injector,marinating injectors,pickle injector
Red meat and poultry injection machine with capacity of needles 50
Red meat and poultry injection machine with capacity of needles 74
Red meat and poultry injection machine with capacity of needles 118
Red meat and poultry injection machine with capacity of needles 236
Tumbler series:vacuum tumbler,meat tumbler
Small capacity vacuum tumbler and massager with capacity 200L and 500L
Medium capacity vacuum tumbler and massager with capacity 1000L and 1600L
High capacity vacuum tumbler and massager with capacity 2500L and 3500L
Turnover type vacuum tumbler and massager with capacity 2500L
Manual Brine Injector,Vacuum Tumbling Machine,Industrial Meat Tenderizer,Meat Tumbler,Poultry Meat Injector,Fish Injector,Red Meat Injector
Helper Machinery Group Co., Ltd. , https://www.helperfoodsolution.com