Successively biaxially stretched polyglycolic acid film, process for producing the successively biaxially stretched polyglycolic acid film, and multilayered film

Abstract

Disclosed is a process for producing a successively biaxially stretched polyglycolic acid film comprising a step (1) of unidirectionally stretching an amorphous polyglycolic acid sheet at a stretching temperature of 40 to 70 DEG C and at a primary stretch ratio of 2.5 to 7.0 to form a uniaxially stretched film, a step (2) of passing the uniaxially stretched film through an environment having a temperature which is in a range of 5 to 40 DEG C and is at least 5 DEG C below the stretching temperature of the step (1), a step (3) of stretching the uniaxially stretched film in a transverse direction transversely to the stretching direction in the step (1) at a stretching temperature, which is in a range of 35 to 60 DEG C and is at least 3 DEG C above the temperature adopted in the step (2), to form a biaxially stretched film having an area ratio of 11 to 30, and a step (4) of heat treating the biaxially stretched film at 70 to 200 DEG C.

Description

technical field [0001] The present invention relates to a sequentially biaxially stretched polyglycolic acid film excellent in gas barrier properties, mechanical strength, transparency, heat shrinkage resistance, and the like, and a method for producing the same. The successively biaxially stretched polyglycolic acid film of the present invention has excellent transparency due to its small oxygen transmission coefficient, high falling ball impact strength and puncture strength, and low haze value, and is excellent in heat shrinkage resistance due to heat setting, so it can It is ideally used in a wide range of technical fields in the form of single-layer or multi-layer films, such as packaging materials such as food, pharmaceuticals, and electronic materials; medical materials such as culture plates, artificial skin, and scaffolds, etc. Background technique [0002] Polyglycolic acid is known to be decomposed by microorganisms or enzymes present in nature such as soil and se...

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Problems solved by technology

[0014] Therefore, although various methods of sequentially biaxially stretching polyglycolic acid to manufacture biaxially stretched polyglycolic acid films have been proposed, most of the methods have the feature of mainly controlling the stretching temperature

However, relying on existing methods that only control the stretching temperature, it is difficult to manufacture sequentially biaxially stretched polyglycolic acid films with various properties that meet the requirements on an industrial scale

[0015] More specifically, when the method of controlling the stretching temperature is used, fluctuations and whitening of the film surface tend to occur during the stretching process.

In the roll / expander type sequential biaxial stretching method using a combination of a stretch roll and a tenter, since the uniaxially stretched film obtained by roll stretch molding tends to shrink, it is difficult to The chucks of the machine securely hold both ends for biaxial stretching

Therefore, it is extremely difficult to stably and continuously produce sequentially biaxially stretched polyglycolic acid films excellent in gas barrier properties, mechanical properties, transparency, heat shrinkage resistance, etc.

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