TPV can be used as packaging material

When food packaging requires rubber parts, food contact grade thermoplastic vulcanizates (TPVs) are worthy of the choice of processors. TPV has real rubber properties equal to or better than traditional thermoset rubber. TPV, like standard thermoplastics, has high processing efficiency and low processing costs. Therefore, the use of this material for component production can significantly reduce costs. TPV can be processed through injection molding and extrusion equipment and can be fully recycled.

The lid of a stylish beverage container is made of food grade Santoprene TPV. The food contact grade Santoprene(R) thermoplastic vulcanizate is an engineering thermoplastic elastomer (TPE). FDA and EU regulations. Compared with thermoset rubber, this material has the advantages of low toxicity and low cost, and is particularly suitable for rubber products that are in direct contact with foods and beverages. In terms of chemical composition and morphology, this TPV is completely different from the traditional type of thermosetting rubber, and there is no problem of multiple chemical residue in the thermosetting rubber.

Microwave resistant

Polypropylene (PP) containers have long been used in microwave ovens. Santoprene's (TPV) TPV elastomer is a PP/EPDM rubber elastomer alloy, so there is reason to believe that containers made of this rubber (including bowls, cups, plates, etc.) are more flexible and less brittle. Hardness grade (40 and 50 Shore D) food contact Santoprene (r) TPV elastomers are suitable for use as food and beverage containers for use in microwave ovens.

To test the effect of microwave oven irradiation, 20 ounces of drinking water or tomato soup was partially filled with 50 Shore D duPont grade TPV elastomer molded bowls for testing. Then, these liquid-filled bowls were placed in a 1250W microwave oven for microwave irradiation for 1, 3, and 9 minutes, respectively; the bowl was moved in position when the irradiation time was more than halfway. After each irradiation was completed, the micro bar sample was extracted from each bowl bottom; then, the sample was compared with the control micro bar not irradiated with the microwave oven to determine the stress-strain characteristic retention value.

All TPV bowls exposed to microwave irradiation showed ideal results in terms of final tensile strength, final elongation retention, and 100% modulus. These characteristics are basically the same as those of the control bowl, and the results are the same when using the PP test. The data shows that food-contact TPVs have excellent resistance to microwave irradiation and can be considered when injecting containers or seals used in microwave ovens.

At the same time, the discoloration measurement using a Hunterlab Tristimulus colorimeter showed that TPV did not show significant contamination after receiving microwave irradiation, and contact with tomato soup was no exception.

Water and steam resistant

Since most foods and beverages contain moisture, it is necessary to measure the resistance of food-grade Santoprene (T) elastomers to long-term soaking in water. The temperature of the rubber in contact with water is generally 0-100°C. If exposed to direct steam, the temperature is as high as 135°C.

According to the ASTM D 471 standard, two food contact grade elastomers with a hardness of 64 Shore A and 40 Shore D were soaked in water at temperatures of 23, 70, and 83°C, respectively, and soaked in 30, 60, 90, 180, and 365. day. Then, changes in hardness, weight, and tensile stress-strain properties were measured to evaluate the effect of water on the elastomer.

After soaking in the above three temperatures for one year, the final tensile strength, final elongation and 100% modulus of the material did not change much, and the hardness change (decrease) was only slight. In each case, the hardness and tensile stress-strain retention values ​​did not exceed the limits specified in the ASTM D 2000 standard. The data shows that after immersing in hot and cold water for up to one year, the above characteristics have little effect. Although the weight is slightly increased, the TPV elastomer completely retains its original characteristics and meets the requirements of food contact grade elastomers.

Since many rubber products will be cleaned at 120°C and 135°C or subjected to direct steam sterilization, tests are performed on 73 Shore A and 40 Shore D hardness elastomers for 15, 30, 75, and 150 minutes, respectively, to determine direct The effect of steam on food contact grade elastomers at 126 °C. The results show no major changes in hardness and tensile stress-strain. Steam contact improves the compression set for both grades. This improvement may be mainly due to rubber annealing rather than the inherent improvement in compression set. Therefore, Santoprene's TPV elastomers show sufficient applicability when they are in direct contact with water and steam at a temperature of 0-135°C.

Resistant to food and drink media

At present, TPV is used for long-term contact with a variety of non-fat foods and beverages. In order to determine the effect of this type of food on the properties and performance of elastomers, it was tested that Shandu Ping (r) TPV elastomers with a Shore hardness level of 55A-50D were soaked in the following foods and beverages at 23°C. 168 hours (1 week): Coca-Cola; Sprite Soft Drinks; Diet Coke; Orange Juice, 100% Concentration; Kraft Mayonnaise; Bordens Whole Fresh Milk, All Mixed; Budweiser; Gallo Rhine Liquor; Heinz Ketchup; Karo Corn syrup, light weight; Heinz apple cider vinegar; Mazola corn oil (vegetable oil); sodium chloride extracted from Morton salt; coffee cooked with Maxwell House coffee.

One week after exposure to food-contact TPV, the effect on weight gain, tensile stress-strain characteristics, and color change was measured.

Tensile stress-strain data shows that neither type of contact has a serious effect on the physical properties of the TPV. In non-fat foods and beverages, the increase in weight is minimal, less than 1%. Only large changes in weight occurred in corn oil and only occurred in rubber grades with low hardness (below 73 Shore A hardness).

The above data clearly shows that food contact grade TPV elastomers are suitable for direct contact with various types of foods and beverages with continuous phase water. TPV rubber has broad prospects and has been applied more and more widely in the food and beverage industry, fully embodying the wide applicability of this material.

In addition to the general food container rubber parts, Santoprene's (TPV) TPE elastomer can also be used as a seal for dishwashers that come in contact with containers. It has been commonly used in the market for 20 years.