Excellent properties and application of the hottes

2022-08-17
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The development of the plastic industry has brought cheap and Wumart packaging to commodities, but the extensive use of plastic products produced from non renewable petroleum resources has also brought serious problems such as resource shortages and environmental pollution to mankind. Polylactide our control of the hardness change and internal and external diameter change of the catheter has been 10 points. The appearance of mature acid membrane (bopla) provides an effective means to solve the above problems. Polylactic acid (PCA) is an environmentally friendly material prepared from lactic acid obtained by starch fermentation. It not only has good physical properties, but also has good biocompatibility and degradation performance. It can be completely decomposed in 2 ~ 3 months under composting conditions, and the raw material is from renewable plants

although PLA has obvious advantages, its use and development are limited because the heat-resistant temperature is too low (softening point 55 ℃). In order to improve the temperature resistance of PLA, people have tried many methods (such as mixing starch or other plastics) to modify it, but the effect is not ideal. After biaxial stretching and heat setting, the heat-resistant temperature of PLA film can be increased to 100 ℃, and the strength and toughness are significantly improved. Therefore, biaxial stretching is one of the best methods to improve the application characteristics of PLA materials

excellent performance characteristics and application trend

except that the temperature resistance of bopla film produced by Shanghai Chemical Plant Co., Ltd. is not as good as pet, other properties are close to or even better than PET (such as optical properties, heat sealability, etc.), which has fully met the performance requirements of general packaging films. An in-depth understanding of the characteristics of bopla membrane will help to expand its field of application. See Table 1 for the comparison of conventional performance indexes between bopla film and BOPET film. The second generation styrene based thermoplastic elastomer SEBS came into being in 1972

table 1bopla film and BOPET film routine performance index comparison table%

project boplabopet test method

tensile strength/mpamd135160din53455

td150160

elongation at break md105100din53455

td9590

transmittance 9288astmd1003

haze 0.52astmd1003

gloss ≥ 110 ≥ 110astmd2457

thermal shrinkage md52.5100 ℃ 1min (PLA)

td50.515 ℃ 15min (PET)

surface tension/mn · m-13838astmd1894

note: MD refers to longitudinal, TD refers to transverse

1 Stability of folding shape

bopla film has better fixation of crease shape than other general plastics (see Figure 1). The measured crease maintenance angle exceeds 90 °, so bopla film in the thickness range of 150 ~ 300um is suitable for making packaging folding boxes

2. Kink retention

bopla film also has excellent performance in twist shape retention (see Figure 2). Its 360 ° kink release retention angle is 277 °, second only to cellophane, but much better than pet, PP, etc. Therefore, bopla film with a thickness of 20 ~ 50um can completely replace pet and other non degradable plastic kink packaging films

3. Optical properties

bopla film has high light transmittance and extremely low haze; The surface gloss is also very good. Therefore, using bopla film metal plating or processing transparent coating products will be more shiny and bright than general plastics

4. Printability

bopla is a strong polar material, and its adhesion to the electroplated coating of printing ink is better than that of corona treated PET film; And because of its high transparency and minimal haze, the color and layering of the inner screen are excellent

5. Heat sealing performance

by adjusting the biaxial tensile orientation and setting process, the heat sealing temperature of bopla film can be controlled at 70 ~ 160 ℃. Shanghai Chemical Plant Co., Ltd. has carried out many tests, using bopla film to heat DuPont high performance materials division, which announced to raise the price of all DuPont Zytel and DuPont Delrin products worldwide. The sealed bags can contain liquid; The film heat sealing and cutting bag is made into a flower sheath; The window film is directly sealed with the carton or envelope by hot pressing without glue

6. Barrier property

bopla film is not only superior to conventional plastics PP and PE in gas barrier performance, but also performs well in oil resistance and odor barrier, which can meet the requirements of conventional packaging

7. Heat shrinkability

compared with the performance indexes of other shrinkable films made of special PLA raw resin (see Table 2), it is found that PLA heat shrinkable film has good comprehensive performance and minimal haze, which is suitable for heat shrinkable film

Table 2 Comparison of performance indexes of heat shrinkable film made of PLA raw material resin and other shrinkable films%

haze, elongation at break, heat shrinkability (100 ℃, 5min)

MD/tdmd/TD

high transparency pla0.63/437/70

high impact pla7.2110/588/68

OPS (tensile PS) 6.0109/606/72

PETG (modified PET) 5.0418/582.5/62.5

pvc194/436.5/56.5

8 Temperature resistance

the temperature resistance of PLA film can be said to be its weakest. Through biaxial stretching and heat setting treatment, Shanghai Chemical Plant Co., Ltd. trial produced a film with a heat shrinkage of ≤ 1% (100 ℃, 1min), which can fully meet the requirements of conventional processing. The company has coated bopla film with water-based coatings, and the trial production results show that bopla is suitable for the coating processing of a variety of coatings, including water-based coatings, under the controlled process conditions

the development prospect is promising

pla has eliminated its fatal weakness after being shaped by biaxial stretching, and also completely shows other unique performance advantages except biodegradability, which undoubtedly opens a door to the plastic packaging market for the application of products

◆ thin film (below 100um)

using the excellent characteristics of bopla, such as kink retention, easy printing, high transparency and high brightness, and heat sealing, in aluminum plating, color printing, thermal composite film; Candy, preserved meat kink packaging film, as well as all kinds of food, office stationery, sanitary washing supplies and other disposable packaging cases and bags have been widely used

◆ thick film (150 ~ 500um)

excellent folding stability and transparency are the advantages of bopla film. Bopla film of about 200um is the first choice for high-grade transparent folding box. The thick sheet after proper stretching improves the toughness and temperature resistance of the sheet. It has a bright prospect for application in food hot pressing, plastic forming Telecom cards, packaging containers and disposable lunch boxes

in a word, biaxial stretching is an effective method to improve the application characteristics of PLA. With the gradual approach of PLA raw material price and processing cost to traditional plastics, the healthy and environmentally friendly packaging using bopla is bound to be accepted and loved by the public

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