KR102064333B1 - Biogradable film - Google Patents

Abstract

A polyhydroxyalkanoate (PHA) resin, a polylactic acid (PLA) resin and an acrylic resin, wherein the polyhydroxyalkanoate (PHA) resin provides a crystalline biodegradable film.

Description

Biodegradable Film {BIOGRADABLE FILM}

It relates to a biodegradable film.

Sheets or films using petroleum resins such as polyvinyl chloride (PVC) are widely used throughout the industry.

Such sheets and films are manufactured by T-die extrusion or calendering using a resin such as polyvinyl chloride (PVC). However, the polyvinyl chloride (PVC) and the like are obtained from crude oil, and supply of raw materials may be difficult depending on petroleum resources.

In addition, the polyvinyl chloride (PVC) -based sheet is easy to discharge harmful substances, and also has a problem that can adversely affect the environment at the time of disposal, in relation to environmentally friendly and harmless to humans, which can be replaced It is necessary to develop eco-friendly sheets.

One embodiment of the present invention provides a biodegradable film having excellent dimensional stability.

In one embodiment of the present invention, a polyhydroxyalkanoate (PHA) resin, a polylactic acid (PLA) resin and an acrylic resin, wherein the polyhydroxyalkanoate (PHA) resin provides a crystalline biodegradable film do.

The biodegradable film provides excellent dimensional stability.

Specifically, the biodegradable film may include a polyhydroxyalkanoate (PHA) resin and a polylactic acid (PLA) resin to implement transparent physical properties and biodegradable effects, and the polyhydroxyalkanoate resin may be crystallized. Dimensional stability can be maximized by using a polyhydroxyalkanoate.

Furthermore, it is suitable for a T-die process and a blow process including an acrylic resin, and can improve flexibility and maximize moldability.

Advantages and features of the present invention, and methods for achieving the same will be apparent with reference to the following embodiments. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms. The present embodiments are merely provided to make the disclosure of the present invention complete, and to fully convey the scope of the invention to those skilled in the art, and the present invention is defined by the scope of the claims. It will be. Like reference numerals refer to like elements throughout.

In addition, in this specification, when a part such as a layer, film, region, plate, etc. is said to be "on" or "upper" another part, it is not only when the other part is "directly over" but also another part in the middle. Also includes. On the contrary, when a part is "just above" another part, there is no other part in the middle. In addition, when a part such as a layer, a film, an area, or a plate is "below" or "below" another part, it is not only when the part is "below" but also another part in the middle. Include. In contrast, when a part is "just below" another part, there is no other part in the middle.

In one embodiment of the present invention, a polyhydroxyalkanoate (PHA) resin, a polylactic acid (PLA) resin and an acrylic resin, the polyhydroxyalkanoate (PHA) resin comprises a crystalline biodegradable film to provide.

In general, with increasing interest in biodegradable films, the demand for films and sheets mixed with polylactic acid resins and acrylic resins continues to increase. The polylactic acid resin is a biodegradable resin that is harmless to humans, but has a disadvantage of high brittleness, difficulty in processing in the form of a film, and slow decomposition rate.

Thus, in one embodiment according to the present invention, the biodegradable film comprises a polylactic acid resin, crystalline polyhydroxyalkanoate resin and acrylic resin, so that the degradable film can achieve dimensional stability while maintaining excellent ductility and durability. Can be.

Specifically, in the case of mixing only the polylactic acid resin and the acrylic resin, the biodegradable film may be easily broken and the decomposition rate may be remarkably slow. However, by including the crystalline polyhydroxyalkanoate resin together, Flexibility, degradation rate and durability can be improved.

Furthermore, by controlling the physical properties of the polyhydroxyalkanoate resin to crystallinity it can maximize the dimensional stability of the biodegradable film.

In the present specification, ?? can be determined by the presence or absence of a crystallization peak when measured by differential scanning calorimetry (DSC) or (TA Instruments, Discovery DSC). Specifically, if there is a crystallization peak, it is crystalline, and if there is no crystallization peak, it is amorphous.

That is, the crystalline polyhydroxyalkanoate resin may mean a polyhydroxyalkanoate resin having a crystalline peak when measured by differential scanning calorimetry.

? Of the polyhydroxyalkanoate resin can be implemented by appropriately controlling the type and composition ratio of the monomers constituting the polyhydroxyalkanoate resin, the dimensions of the biodegradable film is improved based on the appropriate crystallinity Stability may be indicated.

Specifically, the polyhydroxyalkanoate resin is 3-hydroxybutyrate (3-hydroxybutyrate), 3-hydroxyhexanoate (3-hydroxyhexanoate), 4-hydroxybutyrate (4-hydroxybutyrate), 2-hydroxy 2-hydroxybutyrate, 3-hydroxydecanoate, 3-hydroxydodecanoate, 3-hydroxyvalerate and combinations thereof One monomer component selected from the group consisting of may be polymerized or copolymerized.

In one embodiment, the polyhydroxyalkanoate resin may be a copolymer of a mixed monomer component consisting of 3-hydroxybutyrate and 4-hydroxybutyrate, specifically the mixed monomer component is the 4-hydroxybutyrate May be up to 20% by weight.

In another embodiment, the polyhydroxyalkanoate resin may be a copolymer of a mixed monomer component consisting of 3-hydroxybutyrate and 3-hydroxyhexanoate, specifically, the mixed monomer component may be The hydroxyhexanoate may be up to 20% by weight.

The polyhydroxyalkanoate resin may have a weight average molecular weight (Mw) of about 400,000 to about 500,000. When the weight average molecular weight of the polyhydroxyalkanoate resin is maintained in the above range, it can implement excellent durability and moldability, it is possible to easily ensure the flexibility and processability of the film. When the weight average molecular weight of the polyhydroxyalkanoate resin is less than the above range, the melt strength is small and may cause a film formability problem. In addition, when the weight average molecular weight of the polyhydroxyalkanoate resin is more than the above range, the room temperature flexibility is lowered, the melt strength is too large may cause a problem that the moldability is lowered.

Since the biodegradable film is sensitive to temperature and humidity, the glass transition temperature of the polyhydroxyalkanoate resin may be controlled to improve resistance by temperature and humidity. Specifically, the polyhydroxyalkanoate resin may have a glass transition temperature (Tg) of about -10 ° C to about 10 ° C. By maintaining the glass transition temperature of the polyhydroxyalkanoate resin in the above range, it is possible to reduce the dimensional change between room temperature and high temperature. When the glass transition temperature of the polyhydroxyalkanoate resin is less than the above range, not only the dimensional change of the film increases but also the durability may decrease. In addition, when the glass transition temperature of the polyhydroxyalkanoate resin is more than the above range, a large change in the size of the film, may cause a problem of poor film production processability.

The degree of crystallinity of the polyhydroxyalkanoate resin may be about 5% to about 30%. The? 甦 ㅘ ?? indicates the ratio of the crystalline polymer in the polymer, and the crystallinity can be derived using the following formula. Specifically, the crystallinity is obtained by DSC measurement, the Tm value is obtained, the enthalpy (ΔHm) at Tm is obtained by area integration, and then the ratio with the enthalpy (ΔHm ^ㅇ ) value when the substance has 100% crystallinity. Can be obtained as

[expression]

% Crystallinity = 100 * {△ H _m / △ Hm ^ㅇ }

When the degree of crystallinity of the polyhydroxyalkanoate resin maintains the above range, flexibility and processability can be easily ensured. When the degree of crystallinity of the polyhydroxyalkanoate resin is less than the above range, blocking problems may occur during film processing, and there is a problem that the dimensional stability of the film is inferior. When the degree of crystallinity of the polyhydroxyalkanoate resin is more than the above range, the degree of crystallinity is too high may cause a problem of inferior flexibility at room temperature after film formation.

The film may include about 30% to about 50% by weight of the polyhydroxyalkanoate resin. By maintaining the weight percent range of the polyhydroxyalkanoate resin, it is possible to implement excellent processability, flexibility and dimensional stability. When the polyhydroxyalkanoate resin is less than the weight percent range, the flowability during processing may be lowered, thereby causing difficulty in the process, and the flexibility may be lowered to weaken the impact resistance. When the polyhydroxyalkanoate resin is more than the weight% range, hardness and dimensional stability may be lowered, and workability may be deteriorated.

By including the polylactic acid resin together with the polyhydroxyalkanoate resin, it is possible to improve the hardness and thermal stability of the biodegradable film.

Specifically, the polylactic acid resin may be a crystalline polylactic acid resin or an amorphous polylactic acid resin. Crystallinity and amorphousness of the polylactic acid resin are determined by the mixing ratio of the monomers and the synthetic conditions.

For example, when the polylactic acid resin is crystalline polylactic acid, processability and durability of the film can be easily ensured, and when the polylactic acid resin is amorphous polylactic acid, the flexibility of the film can be easily secured. have.

The polylactic acid resin may have a weight average molecular weight of about 400,000 to about 500,000. When the weight average molecular weight of the polylactic acid resin is maintained in the above range, it is possible to implement excellent durability and thermal stability, it is possible to easily ensure the processability and flexibility of the film. When the weight average molecular weight of the polylactic acid resin is less than the above range, the workability is lowered, and a thermal decomposition problem may occur. In addition, when the weight average molecular weight of the polylactic acid resin is more than the above range, there may be a problem that the hardness and durability decreases.

The film may include about 30% to about 50% by weight of the polylactic acid resin. By maintaining the polylactic acid resin in the weight% range, it is possible to easily secure the advantages of processing properties and dimensional stability while maintaining excellent thermal stability and flexibility. When the polylactic acid resin is less than the weight% range, thermal stability and hardness may be lowered, and a problem of deterioration in flowability may occur during processing. When the polylactic acid resin is more than the weight% range, the hardness is too high, the usability after film forming may be lowered, durability may be lowered, and workability may be deteriorated.

By including the acrylic resin together with the polyhydroxyalkanoate resin and the polylactic acid resin, it is possible to maximize the mechanical properties of the biodegradable film, specifically to improve impact resistance, weather resistance, transparency and processability In addition, it is possible to secure an advantage of easy recycling.

Specifically, the acrylic resin may include one selected from the group consisting of methyl acrylate, butyl acrylate, ethyl acrylate, and combinations thereof.

The acrylic resin may have a weight average molecular weight of about 50,000 to about 150,000. By maintaining the weight average molecular weight of the acrylic resin in the above range, it is possible to easily ensure the processing properties and the transparency of the film while maintaining excellent impact resistance and weather resistance. When the weight average molecular weight of the acrylic resin is less than the above range, the impact resistance and durability may be lowered, and the problem of poor film processability may occur. When the weight average molecular weight of the acrylic resin is more than the above range, compatibility with the polylactic acid resin and the polyhydroxyalkanoate resin may be lowered, and the transparency of the film may be reduced.

The film may include about 20% to about 40% by weight of the acrylic resin. By maintaining the acrylic resin in the weight% range, it is possible to improve the mechanical properties and moldability of the biodegradable film, it is possible to easily ensure the processing properties and transparency of the film. When the acrylic resin is less than the weight% range, the durability, transparency, impact resistance and flexibility of the biodegradable film may be lowered. When the acrylic resin is more than the weight% range, the stiffness and strength of the biodegradable film may be lowered, and the problem of poor workability may occur.

The film may further include an additive, and the additive may include one selected from the group consisting of thermal stabilizers, light stabilizers, UV stabilizers, slip agents, and combinations thereof.

The slip agent may impart a smooth flow of the resin during film processing, and may provide anti-blocking property and release property after film formation. For example, a slip agent based on a component of the high amide family may be used.

The film includes the polyhydroxyalkanoate resin, the polylactic acid resin, and the acrylic resin, and the film composition is converted into the biodegradable film by T-die processing or blow processing. Can be prepared.

In the past, calender processing was used to fabricate a biodegradable thin film, but when calendering is used, thin film may be stretched or the thickness may be difficult to control due to high temperature rolling, and thermal decomposition may occur in the process. there was.

Thus, the film may be manufactured through the T-die processing or blow processing to produce the biodegradable film.

In detail, when the biodegradable film is manufactured, when the T-die processing or the blow processing is performed, the thickness variation and the uniformity of the film may be easily secured compared to the calendar processing. .

For example, in the case of a T-die processing, it is possible to process at about 140 ° C to about 160 ° C, and when the T-die processing temperature is maintained in the above range, processability, formability and thickness control This is easy, and thickness variation and uniformity of a film can be easily ensured. When the tee-die processing temperature is less than the above range, the polylactic acid or the acrylic resin does not melt, so processing may be difficult. If the T-die processing temperature exceeds the above range, a problem may occur that the polyhydroxyalkanoate resin is pyrolyzed.

Furthermore, the biodegradable film includes a crystalline polyhydroxyalkanoate resin, maximizes flowability, can be optimized for T-die processing or blow processing, the transparency of the film The uniformity can be easily ensured.

The biodegradable film described above may have a thickness of about 30 μm to about 50 μm. By maintaining the thickness of the biodegradable film in the above range, it is possible to implement excellent flexibility while maintaining the appropriate durability and transparency of the biodegradable film. When the thickness of the biodegradable film is less than the above range, durability and strength may be lowered, and a problem may occur in film processability. When the thickness of the biodegradable film exceeds the above range, flexibility and transparency may be lowered.

The following presents specific embodiments of the present invention. However, the embodiments described below are merely for illustrating or explaining the present invention in detail, and thus the present invention is not limited thereto.

< Example  And Comparative example >

Example  One

A film composition comprising 35 wt% of a crystalline polyhydroxyalkanoate resin (KA151, X151A), 30 wt% of crystalline polylactic acid (Natureworks) and 35 wt% of an acrylic resin (Kuraray) was prepared.

Next, the film composition was introduced into a T-die (EM, custom-made), the film composition was melted at 160 ° C., and then extruded on a 2 mm T-die lip to prepare a 50 μm thick film. A biodegradable film sample of 100 mm length was produced.

Example  2:

Biodegradable films were prepared in the same manner and conditions as in Example 1 except that the polylactic acid included in the film composition was amorphous.

Example  3 :

Except for preparing a film composition comprising 50% by weight of crystalline polyhydroxyalkanoate resin (KANEKA, X151A), 15% by weight of crystalline polylactic acid (Natureworks) and 35% by weight of acrylic resin (Kuraray) Then, a biodegradable film was prepared in the same manner and in the same manner as in Example 1.

Comparative example  One:

Except for preparing a film composition which is free of crystalline polyhydroxyalkanoate resin (KANEKA, X151A) and comprises 30% by weight of crystalline polylactic acid (Natureworks) and 70% by weight of acrylic resin (Kuraray). In the same manner and in the same manner as in Example 1, a biodegradable film was prepared.

Comparative example  2:

A biodegradable film was prepared under the same method and conditions as in Example 1 except that the polyhydroxyalkanoate resin included in the film composition was amorphous.

<Evaluation>

Experimental Example  1: Dimensional Stability Evaluation

After measuring the lengths of the width, length and thickness of the biodegradable films prepared according to Examples and Comparative Examples, after 6 hours storage at 80 ℃ and 2 hours at room temperature again, by measuring the dimensions to measure the rate of dimensional change The results are shown in Table 1 below.

Dimensional rate of change (%) Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Longitudinal direction -2.1% -1.0% -1.5% -13.8% -52.6% Portrait orientation 0.6% -3.2% -2.5% 2.8% -1.6%

Claims (13)

Polyhydroxyalkanoate (PHA) resins, polylactic acid (PLA) resins and acrylic resins,
The polyhydroxyalkanoate (PHA) resin is crystalline,
The acrylic resin includes one selected from the group consisting of methyl acrylate (Methyl Acrylate), butyl acrylate (Buthyl Acrylate), ethyl acrylate (Ethyl Acrylate), and combinations thereof,
30 wt% to 50 wt% of the polyhydroxyalkanoate resin,
20 wt% to 40 wt% of the acrylic resin,
It contains more acrylic resin than the polylactic acid resin
Biodegradable film.
The method of claim 1,
The polyhydroxyalkanoate resin is 3-hydroxybutyrate (3-hydroxybutyrate), 3-hydroxyhexanoate (3-hydroxyhexanoate), 4-hydroxybutyrate (4-hydroxybutyrate), 2-hydroxybutyrate ( Polymerized or copolymerized with one monomer component selected from the group consisting of 2-hydroxybutyrate, 3-hydroxydecanoate, 3-hydroxydodecanoate and combinations thereof
Biodegradable film.
The method of claim 1,
The polyhydroxyalkanoate resin has a weight average molecular weight of 400,000 to 500,000
Biodegradable film.
The method of claim 1,
The polyhydroxyalkanoate resin has a glass transition temperature (Tg) of -10 ° C to 10 ° C.
Biodegradable film.
The method of claim 1,
The degree of crystallinity of the polyhydroxyalkanoate resin is 5% to 30%
Biodegradable film.
delete The method of claim 1,
The polylactic acid resin is a crystalline polylactic acid resin or an amorphous polylactic acid resin
Biodegradable film.
The method of claim 1,
The polylactic acid resin has a weight average molecular weight of 400,000 to 500,000
Biodegradable film.
The method of claim 1,
30 wt% to 50 wt% of the polylactic acid resin
Biodegradable film.
delete The method of claim 1,
The acrylic resin has a weight average molecular weight of 50,000 to 150,000
Biodegradable film.
delete The method of claim 1,
30 μm to 50 μm thick
Biodegradable film.