WO2018056539A1 - Biodegradable resin composition and biodegradable article manufactured therefrom - Google Patents

Abstract

The present invention relates to a biodegradable resin composition and a biodegradable article manufactured therefrom, the biodegradable resin composition comprising: a base resin composition; a plasticizer; and a compatibilizer, the base resin composition comprising (a) 20-30 wt% of poly lactic acid (PLA), (b) 60-70 wt% of at least one biodegradable polyester resin selected from the group consisting of aliphatic polyester resins, excluding the PLA, and aliphatic/aromatic polyester resins, (c) 3-10 wt% of calcium carbonate (CaCO₃), and (d) 3-10 wt% of titanium dioxide (TiO₂), wherein (e) the sum of the contents of calcium carbonate and titanium dioxide is 10-20 wt%. The biodegradable resin composition comprising polylactic acid according to the present invention can produce a biodegradable article which has improved whiteness and hiding power and reduced gloss while having excellent tensile strength, tensile elongation, and tearing strength.

Description

Biodegradable Resin Compositions and Biodegradable Articles Made Therefrom

The present invention relates to a biodegradable resin composition and a biodegradable article prepared therefrom, and more particularly, to a biodegradable resin composition capable of producing a biodegradable article having excellent mechanical properties, improved whiteness and hiding power, and low gloss. And a biodegradable bag such as a biodegradable film made therefrom or a shopping bag made from the film.

Synthetic resins such as polyethylene, polystyrene, polypropylene, and polyvinyl chloride have been widely used in trash bags, rollbacks, shopping bags, food packaging, building materials and home appliances in various fields throughout the industry, and are indispensable in everyday life. Occupies. Although these synthetic resins are very durable, there is a problem in that degradability in the natural state adversely affects the ecosystem and causes environmental destruction upon disposal after use. Among these, the proportion of disposable products using the resins is increasing, which is a big social problem and also causes an increase in economic cost.

What is presented as a solution to the above problems is to use a biodegradable resin. As the biodegradable resin, polylactic acid (PLA), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), polybutylene adipate-co-terephthalate (PBAT), etc. are commercially available. . These resins can be biodegraded due to the action of the enzymes produced by environmentally existing microorganisms to break down into low molecular weight materials and finally to water and carbon dioxide.

Among these, PLA has the advantage of excellent rigidity and good transparency in addition to biodegradability, but brittle is strong, brittle, brittle, heat deformation temperature is low as low as 60 ℃ low thermal stability, very low flexibility and tear characteristics film If manufactured with a disadvantage that is easily torn.

In order to overcome this problem, research is being actively conducted to improve physical properties by blending PLA and other biodegradable polyester resins.

For example, Patent Document 1 (Korean Unexamined Patent Publication No. 10-2001-0032052) is made by containing a polylactic acid-family polymer and other aliphatic polyester in a weight ratio of 80:20 to 20:80. It discloses about a film and it is described that according to the said method, a brittleness improves and the biodegradable film excellent in sealing property is obtained. However, there is a problem that the tensile strength of the film produced is poor due to lack of compatibility between the polylactic acid polymer and other aliphatic polyester.

Accordingly, Patent Document 2 (Korean Patent Publication No. 10-2012-0131961) uses the montmorillonite-based nanoclay together with PLA to manufacture a PBSA blend to improve the compatibility between the resins. A method of increasing the tensile strength and the elongation rate of the biodegradable film prepared using the present invention was suggested. However, according to Patent Document 2, although the tensile strength and elongation of the produced film was slightly improved, it did not show an improvement effect on the tear strength.

In addition, the biodegradable film prepared according to the prior documents may be insufficiently limited to the application of products such as shopping bags or garbage bags for mart due to insufficient whiteness, hiding power, glossiness, and the like.

[Preceding technical literature]

[Patent Documents]

(Patent Document 1) KR1020010032052 A

(Patent Document 2) KR1020120131961 A

The problem to be solved by the present invention is a biodegradable resin composition comprising PLA and an inorganic material capable of producing a biodegradable article having excellent tensile strength, tensile elongation and tear strength and improved whiteness and hiding power and low gloss To provide.

Another object of the present invention is to provide a biodegradable article prepared from the biodegradable resin composition.

In order to solve the above problems, the present invention (a) 20 to 30% by weight of poly lactic acid (PLA), (b) made of an aliphatic polyester resin and aliphatic / aromatic polyester resin other than the PLA 60 to 70% by weight of at least one biodegradable polyester resin selected from the group, (c) 3 to 10% by weight of calcium carbonate (CaCO ₃ ) and (d) 3 to 10% by weight of titanium dioxide (TiO ₂ ), ( e) a basic resin composition having a total content of calcium carbonate and titanium dioxide in an amount of 10 to 20% by weight; Plasticizers; And it provides a biodegradable resin composition comprising a compatibilizer.

In the base resin composition, the content ratio of titanium dioxide: calcium carbonate is preferably 1: 1 to 1: 2 (by weight).

The (b) biodegradable polyester resin is poly butylene adipate-co-terephthalate (PBAT), poly butylenes succinate (PBS), polybutylene succinate It may include at least one selected from the group consisting of poly butylene succinate-co-adipate (PBSA) and poly hydroxyl alkanoate (PHA).

The amount of the plasticizer may be 0.1 to 1.0 parts by weight based on 100 parts by weight of the base resin composition, the plasticizer in the group consisting of dioctyl adipate (DOA), citric acid ester and fatty acid ester It may include at least one selected from the group consisting of at least one ester plasticizer, citric acid (citric acid), polyethylene glycol (PEG) and polypropylene glycol (PPG).

The content of the compatibilizer may be 0.1 to 0.5 parts by weight based on 100 parts by weight of the base resin composition, the compatibilizer is a polyisocyanate, a styrene-acrylate copolymer having an epoxy functional group and a carbodiimide It may include one or more selected from the group consisting of.

The present invention also provides a biodegradable article prepared from the biodegradable resin composition.

In this case, the biodegradable article may be a biodegradable film, or may be a biodegradable envelope prepared from the biodegradable film.

The biodegradable resin composition comprising polylactic acid according to the present invention comprises calcium carbonate (CaCO ₃ ) and titanium dioxide (TiO ₂ ) in an appropriate content and ratio to provide a biodegradable article having excellent whiteness and hiding power and reduced gloss. It can manufacture.

In addition, the biodegradable resin composition may include a suitable plasticizer and a compatibilizer to prepare a biodegradable article having excellent mechanical properties such as tensile strength, tensile elongation and tear strength.

The present invention (a) 20 to 30% by weight of poly lactic acid (PLA), (b) at least one biodegradable polyester selected from the group consisting of aliphatic polyester resins and aliphatic / aromatic polyester resins other than the PLA Resin 60 to 70% by weight, (c) 3 to 10% by weight of calcium carbonate (CaCO ₃ ) and (d) 3 to 10% by weight of titanium dioxide (TiO ₂ ), (e) of the calcium carbonate and titanium dioxide A basic resin composition having a total content of 10 to 20% by weight; Plasticizers; And a biodegradable resin composition comprising a compatibilizer and a biodegradable article prepared therefrom.

First, look at in detail for the biodegradable resin composition according to the present invention.

The above (a) PLA is obtained by polymerizing lactic acid or ring-opening polymerization of lactide, which is relatively inexpensive and has advantages as a raw material for biodegradable resins. Such PLA may be at least one selected from the group consisting of poly L-lactic acid, poly D-lactic acid and poly L, D-lactic acid.

The content of PLA is 20 to 30% by weight based on the weight of the base resin composition. When the content of PLA is less than 20% by weight, the mechanical properties such as tensile strength of the finally produced biodegradable article are lowered, and the content of relatively expensive biodegradable polyester resin is increased, thereby reducing economic efficiency. On the other hand, when the content of PLA exceeds 30% by weight, brittleness of the biodegradable article is increased, resulting in a problem in that tensile elongation, tear strength and impact strength are lowered.

(B) at least one biodegradable polyester resin selected from the group consisting of aliphatic polyester resins and aliphatic / aromatic polyester resins other than PLA, improves the brittleness of the PLA to improve tensile elongation, tear strength and impact strength It is used as a base resin of the biodegradable resin composition according to the present invention together with the PLA to produce a good biodegradable article.

The content of such biodegradable polyester resin is 60 to 70% by weight based on the weight of the base resin composition. When the content of the biodegradable polyester resin composition is less than 60% by weight, the effect of improving the brittleness of the PLA is insignificant, resulting in a problem that the tensile elongation and tear strength of the biodegradable article are lowered. The mechanical properties such as tensile strength of the article is poor and has the disadvantage of low economic efficiency.

The biodegradable polyester resin is poly butylene adipate-co-terephthalate (PBAT), poly butylenes succinate (PBS), polybutylene succinate-co- It may include at least one selected from the group consisting of adipate (poly butylene succinate-co-adipate (PBSA) and poly hydroxyl alkanoate (PHA), preferably PBAT.

The biodegradable resin composition according to the present invention is titrated with two inorganic additives consisting of calcium carbonate (CaCO ₃ ) and titanium dioxide (TiO ₂ ) for the purpose of simultaneously obtaining the hiding power, the whiteness improvement and the gloss reduction effect of the biodegradable article. Include in content.

The content of (c) calcium carbonate (CaCO ₃ ) is 3 to 10% by weight based on the weight of the base resin composition. When the content of the calcium carbonate (CaCO ₃ ) is less than 3% by weight, there is a problem that the hiding power of the biodegradable article is lowered, whereas when the content of more than 10% by weight, the b value of the chromaticity value is lowered and the whiteness is lowered. .

The content of the (d) titanium dioxide (TiO ₂ ) is 3 to 10% by weight based on the weight of the base resin composition. When the content of the titanium dioxide (TiO ₂ ) is less than 3% by weight, a problem arises in that the whiteness of the biodegradable article is lowered. On the other hand, when the content of the titanium dioxide (TiO ₂ ) is more than 10% by weight is not well stretched, there is a difficulty in producing a biodegradable article in the form of a film, for example.

In the base resin composition of the composition of the present invention, preferably, the total content of the calcium carbonate and titanium dioxide is 10 to 20% by weight, and in particular, the content ratio of the titanium dioxide: calcium carbonate is 1: 1 to 1: It is more preferable that it is 2 (weight basis).

When the total content of the calcium carbonate and titanium dioxide is less than 10% by weight, there is a problem of insufficient hiding power and high glossiness, and stiffness when manufacturing an article such as a film using the biodegradable resin composition according to the present invention. Lack of stiffness causes a problem that productivity is lowered when the film is processed into a final product such as a shopping bag. On the other hand, when the total content of the calcium carbonate and titanium dioxide exceeds 20% by weight, the tensile elongation is lowered when the article is made of an article such as a film, resulting in a problem that the sealing strength when processing the final product, such as shopping bags.

When the content ratio of titanium dioxide: calcium carbonate is less than 1: 1, glossiness may increase, and when the ratio exceeds 1: 2, a problem may occur in that the color of the biodegradable article becomes yellow.

On the other hand, the plasticizer is an additive that is added to the polymer to modify the properties and functions, such as processability, flexibility, the content of the plasticizer is preferably 0.1 to 1.0 parts by weight based on 100 parts by weight of the base resin composition. If the content of the plasticizer is less than 0.1 parts by weight, there is a concern that the improvement of physical properties may be insignificant. On the other hand, if the content of the plasticizer exceeds 1.0 parts by weight, the plasticizer may be included in an excessive amount to migrate to the surface after the biodegradable article is manufactured. The sealing strength of the shopping bag may be gradually weakened, which may cause a problem of degrading the quality of the biodegradable final product.

The plasticizer may be at least one ester plasticizer selected from the group consisting of dioctyl adipate (DOA), citric acid ester and fatty acid ester, citric acid, polyethylene glycol (PEG) and It may include one or more selected from the group consisting of polypropylene glycol (PPG). At this time, since the ester plasticizer has an ester structure similar to PLA, it can improve the tensile elongation of the brittle and biodegradable articles of PLA can be preferably used. In particular, DOA in the ester-based plasticizer is excellent in compatibility with PLA can minimize the surface migration of biodegradable articles, thereby making it possible to prepare a biodegradable article with excellent sealing strength can be used more preferably.

The compatibilizer is added to ensure compatibility of PLA and biodegradable polyester resins other than PLA, and serves to improve mechanical properties such as tensile strength and tear strength of biodegradable articles. The content of the compatibilizer is preferably 0.1 to 0.5 parts by weight based on 100 parts by weight of the base resin composition. When the content of the compatibilizer is less than 0.1 parts by weight, the compatibility between the resins may be lowered, whereas mechanical properties may be lowered. On the other hand, when the content of the compatibilizer exceeds 0.5 parts by weight, the melt index (MI) may be excessively low, resulting in a biodegradable article. There is a fear that the workability is poor.

The compatibilizer may include at least one selected from the group consisting of polyisocyanate, styrene-acrylate copolymer having an epoxy functional group, and carbodiimide. As the styrene-acrylate copolymer having the epoxy functional group, for example, the "JONCRYL" (registered trademark) series of BASF can be used.

Preferably, polyisocyanate may be used as the compatibilizer, and more preferably trifunctional polyisocyanate, such as trifunctional polyisocyanate represented by Formula 1 below, may be used.

Formula 1

In addition, the biodegradable resin composition according to the present invention may further include an antioxidant.

The antioxidant prevents crosslinking of the polymer that may occur during the process of processing, and serves to prevent discoloration as well as to maintain long-term physical properties of the finished product. The content of the antioxidant is preferably 0.1 to 5 parts by weight based on 100 parts by weight of the base resin composition. When the content of the antioxidant is less than 0.1 parts by weight, the antioxidant effect is insignificant, which may lower the durability of the biodegradable article. On the other hand, if the content of the antioxidant is more than 5 parts by weight, the effect of the content may be insufficient, rather, the excessive amount of the antioxidant may be transferred to the surface may not look good.

The antioxidant may include a primary antioxidant and a secondary antioxidant. Specifically, the primary antioxidant is to inhibit the generation of unstable free radicals generated by the oxidation action or to make the free radicals in a stable form, phenolic or aromatic amine-based antioxidants are typical . The secondary antioxidant serves to inhibit the production of another unstable free radical that may be caused by the oxidation of hydroperoxides formed by the combination of unstable free radicals with oxygen, and phosphorus or thio-based antioxidants Can be used.

The present invention also provides a biodegradable article prepared from the biodegradable resin composition.

The biodegradable article may be a biodegradable film prepared from the biodegradable resin composition. The biodegradable film can be produced using a film maker according to a conventional method. In this case, calcium carbonate (CaCO ₃ ) and titanium dioxide (TiO ₂ ) may be used for film production in the form of a master batch (M / B) chip to improve dispersibility.

Thus prepared biodegradable film is excellent in tensile strength, tensile elongation and tear strength can be used to replace the existing synthetic resin.

The biodegradable article may be a biodegradable bag made from the biodegradable film, and may be used, for example, in a garbage bag, a roll bag, a shopping bag, or the like. In addition, the biodegradable article may be widely commercialized in fields such as food packaging materials. In particular, the biodegradable film prepared according to the present invention is excellent in whiteness, hiding power and low glossiness, when used as a shopping bag for mart, it is more preferable to satisfy the needs of consumers.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example  One

Poly butylene adipate-co-terephthalate (PBAT) (ENPOL PBG7070, S-Enpol) 67% by weight, poly lactic acid (PLA) (PLA 4032D, NatureWorks) 23 A wt%, 7 wt% TiO ₂ (Cosmo Chemical) and ₃ wt% CaCO ₃ (GTL chemical) were added to the mixer to prepare a base resin composition mixture.

Subsequently, a plasticizer (dioctyl adipate, Aekyung emulsification) based on 100 parts by weight of the base resin composition mixture and the base resin composition in a twin-screw extruder (manufactured by Changsung P & R, L / D: 36/1, diameter: 24.2 mm) 0.3 parts by weight and 0.25 parts by weight of a compatibilizer (trifunctional polyisocyanate, Aekyung Chemical) were added and melt kneaded at 170 ° C. to prepare a biodegradable resin composition pellet.

Thereafter, the pellets were melt kneaded at a processing temperature of 170 ° C. using a Eugene Engineering Co., Ltd. YJF-2 (diameter: 60 mm) film molding machine to prepare a biodegradable film having a width of 400 mm and a thickness of 50 μm, 300 m.

Examples 2-4 and Comparative Examples 1-3

Biodegradable film was prepared in the same manner as in Example 1 except that the content of PBAT, PLA, TiO ₂ , CaCO ₃ , plasticizer and compatibilizer were adjusted as described in Table 1 below.

The physical properties of the films prepared in the above Examples and Comparative Examples were evaluated by the following method.

<Evaluation Method>

1. Melt index (MI)

The melt index of the biodegradable resin composition (pellet state) prepared according to Examples 1 to 4 and Comparative Examples 1 to 3 was measured according to ASTM D1238. Specifically, the amount (g) flowing through an orifice (radius: 2 mm, length: 8 mm) for 10 minutes under a temperature of 190 ° C. and a 2.16 kg load was measured as a melt index (MI).

2. Chromaticity

The chromaticities L *, a * and b * of the biodegradable films prepared according to Examples 1 to 4 and Comparative Examples 1 to 3 were obtained using a CIE-L * a * b * (CIE 1976) colorimeter using a Konica Minolta colorimeter. Measured at The " L * ", " a * " values and " b * " values are indices of color tone displayed in the CIE-L * a * b * (CIE1976) colorimeter. The value "L *" represents brightness, and the larger this value, the brighter it is. The value "a *" indicates the degree of redness, and the larger this value, the higher the degree of redness. The value "b *" indicates the degree of yellowness, and the larger this value, the higher the yellowness and the lower the whiteness.

3. Tear strength

The tear strength in the longitudinal direction (MD) and the transverse direction (TD) of the biodegradable films prepared according to Examples 1 to 4 and Comparative Examples 1 to 3 using an Elmendorf tear strength analyzer Measured.

4. Tensile Strength and Tensile Elongation

The tensile strength and tensile elongation in the longitudinal direction (MD) and the transverse direction (TD) of the biodegradable films prepared according to Examples 1 to 4 and Comparative Examples 1 to 3 were measured based on JIS K6251-1.

5. hiding power and glossiness

The hiding power of the biodegradable films prepared according to Examples 1 to 4 and Comparative Examples 1 to 3 was measured using a hiding rate measuring instrument (NOVO-SHOADE DUO, Rhopoint Instrument). In addition, the glossiness of the biodegradable film was measured using a gloss meter (Micro-TRI-Gloss, BKY).

		Example 1	Example 2	Example 3	Example 4	Comparative Example 1	Comparative Example 2	Comparative Example 3
PBAT (% by weight)		67	67	62	62	74	74	70
PLA (% by weight)		23	23	25	25	19	19	23
TiO 2 (% by weight)		7	5	9	4.5	5	5	5
CaCO 3 (% by weight)		3	5	4	8.5	2	2	2
Total (% by weight)		100	100	100	100	100	100	100
Plasticizer (parts by weight)		0.30	0.30	0.30	0.30	-	0.30	0.30
Compatibilizer (parts by weight)		0.25	0.25	0.25	0.25	-	0.25	0.25
MI (g / 10min)		3.5	3.6	3.4	3.8	4.7	4.0	3.9
Film chromaticity	L	96	96	97	96	96	96	96
	a	-0.5	-0.5	-0.3	-0.4	-0.7	-0.4	-0.5
	b	1.1	1.0	0.8	1.0	1.3	1.2	1.3
Tear strength (gf)	MD	49	49	48	48	50	60	57
	TD	155	156	156	164	152	165	163
Tensile strength (kgf / cm 2 )	MD	390	385	380	398	332	364	360
	TD	251	253	251	260	250	286	284
Tear elongation (%)	MD	212	215	196	200	196	230	220
	TD	331	337	310	324	350	410	390
Hiding power (%)		68	74	72	76	60	61	62
Glossiness (60 o )		27	24	26	22	36	35	34

* The content units of the plasticizer and the compatibilizer in Table 1 are parts by weight based on 100 parts by weight of the total amount of PBAT, PLA, TiO ₂ and CaCO ₃ .

Referring to Table 1, it can be seen that the biodegradable film prepared according to Examples 1 to 4 is excellent in whiteness and hiding power and low glossiness as compared to the biodegradable film prepared according to Comparative Examples 1 to 3. In particular, in the case of the biodegradable film prepared according to Examples 2 and 4 in which the input ratio of titanium dioxide: calcium carbonate is in the range of 1: 1 to 1: 2 by weight, the hiding power is markedly high and the gloss is also low. It may be more preferably used for the use of biodegradable bags such as shopping bags for marts and the like.

In addition, in the case of pellets prepared from the biodegradable resin compositions prepared according to Examples 1 to 4, the melt index is lower than that of the resin pellets prepared according to Comparative Examples 1 to 3, and thus the biodegradable resin compositions having excellent processability are It can be confirmed that the manufacturing.

In addition, the biodegradable films according to Comparative Examples 2 and 3 prepared by adding a plasticizer and a compatibilizer may be confirmed to exhibit higher tensile strength, tensile elongation and tear strength than the biodegradable films of Comparative Example 1. . Accordingly, the biodegradable films of Examples 1 to 4 were prepared by applying the same plasticizer and compatibilizer content as in Comparative Examples 2 and 3, and a biodegradable film showing excellent physical properties could be prepared.

As described above, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to explain the present invention, and the scope of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto. Should be construed as being included in the scope of the present invention.

Claims (10)

1. (a) 20 to 30% by weight of poly lactic acid (PLA), (b) at least one biodegradable polyester resin selected from the group consisting of aliphatic polyester resins and aliphatic / aromatic polyester resins other than the above PLA 60 ~ 70% by weight, (c) 3-10% by weight of calcium carbonate (CaCO ₃ ) and (d) 3-10% by weight of titanium dioxide (TiO ₂ ), and (e) the total content of calcium carbonate and titanium dioxide is Basic resin composition of 10 to 20% by weight;

   Plasticizers; And

   Biodegradable resin composition comprising a compatibilizer.
2. The method of claim 1,

   Biodegradable resin composition, characterized in that the content ratio of titanium dioxide: calcium carbonate is 1: 1 to 1: 2 (by weight).
3. The method of claim 1,

   The (b) biodegradable polyester resin is poly butylene adipate-co-terephthalate (PBAT), poly butylenes succinate (PBS), polybutylene succinate A biodegradable resin composition comprising at least one selected from the group consisting of poly butylene succinate-co-adipate (PBSA) and poly hydroxyl alkanoate (PHA).
4. The method of claim 1,

   The amount of the plasticizer is biodegradable resin composition, characterized in that 0.1 to 1.0 parts by weight based on 100 parts by weight of the base resin composition.
5. The method of claim 4, wherein

   The plasticizer may be at least one ester plasticizer selected from the group consisting of dioctyl adipate (DOA), citric acid ester and fatty acid ester, citric acid, polyethylene glycol (PEG) and Biodegradable resin composition comprising at least one selected from the group consisting of polypropylene glycol (PPG).
6. The method of claim 1,

   The content of the compatibilizer is biodegradable resin composition, characterized in that 0.1 to 0.5 parts by weight based on 100 parts by weight of the base resin composition.
7. The method of claim 6,

   The compatibilizer is a biodegradable resin composition comprising at least one selected from the group consisting of polyisocyanate, styrene-acrylate copolymer having an epoxy functional group, and carbodiimide.
8. A biodegradable article made from the biodegradable resin composition according to any one of claims 1 to 7.
9. The method of claim 8,

   And wherein the biodegradable article is a biodegradable film made from the biodegradable resin composition.
10. The method of claim 9,

    And wherein said biodegradable article is a biodegradable envelope made from said biodegradable film.