Composition

Abstract

The present specification provides a composition and use thereof. Disclosed in the present specification is the composition, which is prepared from a biodegradable material, can be prepared at low cost while exhibiting improved tensile properties, has an appropriate viscosity such that a dimensional deviation of an injection molded product is minimized during injection molding, and can have improved shape precision. The present specification provides an injection molded product formed using the composition.

Description

Composition

[0001] The present specification discloses compositions and uses thereof.

[0002] With the recent surge in interest in environmental protection and eco-friendliness, the need for biodegradable products is growing. In particular, medical supplies like disposable syringes and medical device parts, which are discarded after one use for hygiene reasons; agricultural products like seedling pots and agricultural trays; and packaging materials, bottles, and containers generate large amounts of waste after use. Therefore, it is necessary to reduce environmental pollution by adopting biodegradable materials that break down naturally.

[0003] These products not only have complex shapes but also require precise dimensional control along with mass production, so production using injection molding is effective in meeting these requirements.

[0004] Representative biodegradable resins used in producing the above products include poly(lactic acid), polyhydroxyalkanoates, polybutylene succinate, or polybutylene adipate terephthalate.

[0005] Among these, polybutylene adipate terephthalate (PAT) has been used to manufacture the aforementioned products due to its high flexibility, excellent impact resistance, thermoplasticity, and excellent biodegradability under composting conditions. However, while PAT has a high elongation at break, its mechanical properties, including Young's modulus, are low and its high viscosity makes injection molded products prone to sagging.

[0006] Accordingly, compounding with various biodegradable materials has been attempted to improve the properties of polybutylene adipate terephthalate, but there is a problem that the tensile properties are reduced due to low compatibility between polybutylene adipate terephthalate and other biodegradable resins.

[0007] The present specification discloses compositions and uses thereof.

[0008] The present disclosure discloses a composition manufactured from a biodegradable material, which exhibits improved tensile properties while being manufactured at a low cost.

[0009] The present specification discloses a composition having an appropriate viscosity, which can minimize dimensional deviation of an injection molded product and improve shape precision during injection molding.

[0010] The present specification discloses an injection molded article formed using the above composition.

[0011] Among the properties mentioned in this specification, if the measurement temperature affects the property value, the property is a property measured at room temperature unless otherwise specifically stated.

[0012] In this specification, the term room temperature means a natural temperature that has not been heated or cooled, and may mean, for example, any temperature within the range of about 10°C to 30°C, or a temperature of about 23°C or 25°C.

[0013] Among the properties mentioned in this specification, if the measurement pressure affects the property value, the property refers to a property measured at atmospheric pressure unless otherwise specifically stated.

[0014] The term atmospheric pressure in this specification may mean a pressure that is neither pressurized nor depressurized, particularly a pressure of the order of atmospheric pressure, for example, a pressure of about 740 mmHg to 780 mmHg.

[0015] Among the properties mentioned in this specification, if the measured humidity affects the result, the property is a property measured at the humidity of the standard state, unless otherwise specified.

[0016] Standard humidity means a relative humidity within the range of 40% to 60%, for example, a relative humidity of about 55% or 60%.

[0017] The present specification discloses a composition.

[0018] The term composition may be a mixture of two or more different polymers. In the composition, the two or more polymers may be simply mixed, or all or at least part of them may be physically or chemically bonded.

[0019] The polymer may refer to a relatively high molecular weight compound formed by covalently linking two or more units. In one example, the lower limit of the polymer content in the composition may be about 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, or 95 wt%, and the upper limit may be about 100 wt%, 98 wt%, 96 wt%, 94 wt%, 92 wt%, or 90 wt%. The content may be within a range that is equal to or greater than any one of the lower limits described above; or within a range that is equal to or greater than any one of the lower limits described above and equal to or less than any one of the upper limits described above.

[0020] The composition may include an acid-modified biodegradable polyester, pulp and an acid-modified biodegradable polyester.

[0021] Although excellent biodegradability can be achieved by using acid-unmodified biodegradable polyester, the acid-unmodified biodegradable polyester has poor strength. Therefore, the mechanical properties of the composition can be enhanced by including pulp together with the acid-unmodified biodegradable polyester. In addition, since pulp is inexpensive, the composition is more economical as the pulp content increases, the biodegradability is excellent, and the content of bio-based carbon can increase. However, pulp contains cellulose, and cellulose is hydrophilic, whereas acid-unmodified biodegradable polyester is hydrophobic. Therefore, the acid-unmodified biodegradable polyester and pulp do not mix well, which causes a problem of low compatibility.

[0022] Accordingly, the composition may include an acid-modified biodegradable polyester that can improve compatibility between the acid-modified biodegradable polyester and pulp.

[0023] The term "compatibility" as used herein may mean that when pulp is dispersed in a matrix of an acid-unmodified biodegradable polyester to form a dispersed phase, the dispersed phase of the pulp is densely and uniformly distributed. In addition, it may mean that strong adhesive force is exhibited at the interface between the acid-unmodified biodegradable polyester and the pulp.

[0024] In order to secure the desired compatibility, biodegradable polyesters having specific physical properties can each be used as the acid-unmodified biodegradable polyester and the acid-modified biodegradable polyester.

[0025] For example, the density of the biodegradable polyester can be controlled. For example, the lower limit of the density of the biodegradable polyester according to ASTM D792 can be about 1 g / ml, 1.1 g / ml, or 1.2 g / ml, and the upper limit can be about 2 g / ml, 1.9 g / ml, 1.8 g / ml, 1.7 g / ml, 1.6 g / ml, 1.5 g / ml, 1.4 g / ml, or 1.3 g / ml. The density can be within a range that is equal to or greater than any one of the lower limits described above; within a range that is equal to or less than any one of the upper limits described above; or within a range that is equal to or greater than any one of the lower limits described above and equal to or less than any one of the upper limits described above.

[0026] The Melt Flow Index (MFI) of the above biodegradable polyester can be controlled. For example, the lower limit of the Melt Flow Index (MFI) (190°C, 2160g) according to ISO1133 of the biodegradable polyester may be about 0.5 g / 10 min, 1 g / 10 min, 1.5 g / 10 min, 2 g / 10 min, 2.5 g / 10 min, 3 g / 10 min, 3.5 g / 10 min, 4 g / 10 min, or 4.5 g / 10 min, and the upper limit may be about 10 g / 10 min, 9 g / 10 min, 8 g / 10 min, 7 g / 10 min, 6 g / 10 min, 5 g / 10 min, 4.5 g / 10 min, 4 g / 10 min, 3.5 g / 10 min, 3 g / 10 min, 2.5 g / 10 min, or 2 g / 10 min. The above MFI (Melt Flow Index) may be within a range that is equal to or greater than any one of the lower limits described above; within a range that is equal to or less than any one of the upper limits described above; or within a range that is equal to or greater than any one of the lower limits described above and equal to or less than any one of the upper limits described above.

[0027] The melting point of the biodegradable polyester can be controlled. For example, the lower limit of the melting point of the biodegradable polyester according to ASTM D2117 can be about 80°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, or 120°C, and the upper limit can be about 200°C, 190°C, 180°C, 170°C, 160°C, 150°C, 140°C, 135°C, 130°C, 125°C, or 120°C. The melting point is within a range that is equal to or greater than any one of the lower limits described above; or within a range that is equal to or less than any one of the upper limits described above; Or, it may be within a range that is equal to or greater than any one of the lower limits described above, and equal to or less than any one of the upper limits described above.

[0028] The glass transition temperature (Tg) of the biodegradable polyester can be controlled. For example, the lower limit of the glass transition temperature of the biodegradable polyester according to ASTM D2117 may be about -100°C, -90°C, -80°C, -70°C, -60°C, -50°C, -40°C, or -30°C, and the upper limit may be about 0°C, -5°C, -10°C, -15°C, -20°C, or -25°C. The glass transition temperature may be within a range that is equal to or greater than any one of the lower limits described above; within a range that is equal to or less than any one of the upper limits described above; or within a range that is equal to or greater than any one of the lower limits described above and equal to or less than any one of the upper limits described above.

[0029] The acid value of the above-described acid-unmodified biodegradable polyester can be controlled. For example, the upper limit of the acid value of the above-described acid-unmodified biodegradable polyester according to ASTM D974 may be about 1.5 mg-KOH / g, 1.4 mg-KOH / g, 1.3 mg-KOH / g, 1.2 mg-KOH / g, 1.1 mg-KOH / g, 1 mg-KOH / g, 0.9 mg-KOH / g, or 0.8 mg-KOH / g, and the lower limit may be about 0.01 mg-KOH / g. The acid value may be within a range that is less than or equal to any one of the above-described upper limits; or within a range that is equal to or greater than any one of the above-described lower limits and less than or equal to any one of the above-described upper limits.

[0030] The above biodegradable polyester may include a unit of the following chemical formula 1 and a unit of the following chemical formula 2.

[0031] [Chemical Formula 1]

[0032]

[0033] In chemical formula 1, L1 and L2 can each independently be an alkylene group or an alkylidene group.

[0034] [Chemical Formula 2]

[0035]

[0036] In chemical formula 2, Ar1 may be an arylene group, and L3 may be an alkylene group or an alkylidene group.

[0037] The term alkylene group, as used herein, refers to a divalent radical formed by the removal of one hydrogen atom from each of two different carbon atoms of an alkane. The alkylene group may have 2 to 20, 2 to 16, 2 to 12, 2 to 8, or 2 to 4 carbon atoms. The alkylene group may be linear, branched, or cyclic. The alkylene group may be optionally substituted with one or more substituents.

[0038] The term alkylidene group, as used herein, refers to a divalent radical formed by the removal of two hydrogen atoms from one carbon atom of an alkane. The alkylidene group may have 1 to 20, 1 to 16, 1 to 12, 1 to 8, or 1 to 4 carbon atoms. The alkylidene group may be linear, branched, or cyclic. The alkylidene group may be optionally substituted with one or more substituents.

[0039] The term arylene group, as used herein, refers to a divalent group having two bonding positions due to the removal of two hydrogens from an aromatic hydrocarbon ring. The aromatic hydrocarbon ring may include a monocyclic or polycyclic ring. The arylene group may be an arylene group having 6 to 30 carbon atoms, 6 to 26 carbon atoms, 6 to 22 carbon atoms, 6 to 20 carbon atoms, 6 to 18 carbon atoms, or 6 to 15 carbon atoms.

[0040] Additionally, the aromatic hydrocarbon ring may be an aromatic hydrocarbon ring that includes at least one non-carbon heteroatom within the ring. For example, the heteroatom may include at least one atom selected from the group consisting of nitrogen (N), oxygen (O), sulfur (S), selenium (Se), and tellurium (Te).

[0041] The above arylene group may be optionally substituted by one or more substituents. In this case, the substituents may be one or more selected from the group consisting of halogen (chlorine (Cl), iodine (I), bromine (Br), fluorine (F)), aryl group, heteroaryl group, epoxy group, alkoxy group, cyano group, carboxyl group, acryloyl group, methacryloyl group, acryloyloxy group, methacryloyloxy group, carbonyl group, and hydroxy group, but are not limited thereto.

[0042] Conventionally, methods for improving compatibility with biodegradable polyester resins have been known, such as using cellulose whose size has been reduced to micrometers or nanometers by ball milling or high-pressure homogenization of pulp. Furthermore, methods for modifying the surface properties of cellulose are known, such as converting hydroxyl groups on the cellulose surface to ester groups to impart hydrophobicity, and introducing siloxane bonds to the cellulose surface using a silane coupling agent to increase interfacial adhesion with the resin. However, these methods have the problem of being complicated and causing increased manufacturing costs.

[0043] This specification has the advantage of simplifying the process and reducing manufacturing costs by using pulp that has not undergone a separate pretreatment process.

[0044] The pulp may be, for example, one or more selected from the group consisting of paper pulp; cotton pulp such as cotton linter or cotton lint; and non-wood pulp such as hemp, wheat straw, or bagasse. Considering availability, etc., paper pulp may be used.

[0045] Examples of the above paper pulp include, but are not limited to, broadleaf kraft pulp, softleaf kraft pulp, chemical pulp, semi-chemical pulp, mechanical pulp, non-wood pulp, or deinked pulp made from waste paper.

[0046] As the above-mentioned hardwood kraft pulp, for example, bleached kraft pulp (LBKP), unbleached kraft pulp (LUKP), or oxygen bleached kraft pulp (LOKP) can be used.

[0047] As the above coniferous kraft pulp, for example, bleached kraft pulp (NBKP), unbleached kraft pulp (NUKP), or oxygen bleached kraft pulp (NOKP) can be used.

[0048] As the above chemical pulp, for example, sulfite pulp (SP) or soda pulp (AP) can be used.

[0049] As the above semi-chemical pulp, for example, semi-chemical pulp (SCP) or chemical ground wood pulp (CGP) can be used.

[0050] As the mechanical pulp, for example, groundwood pulp (GP) or thermomechanical pulp (TMP, BCTMP) can be used.

[0051] As the above non-wood pulp, one or more types of pulp made from raw materials such as paper mulberry, paper mulberry, hemp, and kenaf can be used.

[0052] For example, the pulp may be in an irregular shape, for example, in the form of flakes. For example, the size of the pulp may be within a predetermined range, and when the pulp is in the form of flakes, the size may refer to the length of the longer part of the width or length of the pulp. For example, the lower limit of the size of the pulp may be about 0.01 mm, 0.1 mm, 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, or 5 mm, and the upper limit may be about 100 mm, 80 mm, 70 mm, 60 mm, 50 mm, 40 mm, 30 mm, 20 mm, 10 mm, 9 mm, 8 mm, 7 mm, 6 mm, or 5 mm. The size is within a range that is equal to or greater than any one of the lower limits described above; Or within a range that is less than or equal to any one of the upper limits described above; or within a range that is greater than or equal to any one of the lower limits described above and less than or equal to any one of the upper limits described above.

[0053] When pulp having the above size is used, a more uniform dispersion phase can be formed on the matrix of the acid-unmodified biodegradable polyester. The pulp may be pulp having the above size as is, or pulp ground to have the above size may be used. In addition, two or more types of pulp having different sizes may be used as the pulp. The size of the pulp can be measured by a known method.

[0054] In the past, a compound in which maleic anhydride was grafted onto a biodegradable polyester was used. However, in this case, there was a problem in that it was difficult for a radical to be generated in the middle of the biodegradable polyester chain, or the grafting reaction efficiency was low due to steric hindrance.

[0055] On the other hand, the acid-modified biodegradable polyester of the present invention has the advantage of very high reaction efficiency. Accordingly, when using the acid-modified biodegradable polyester, it is possible to produce an injection-molded article with superior tensile properties, such as tensile strength, Young's modulus, and / or elongation, compared to when using a compound grafted with maleic anhydride.

[0056] The acid-modified biodegradable polyester of the present specification may be a compound containing a functional group represented by the following chemical formula 3 at a terminal.

[0057] [Chemical Formula 3]

[0058]

[0059] For example, the acid-modified biodegradable polyester may be a compound containing a unit of the following chemical formula 4 or chemical formula 5 at the terminal.

[0060] [Chemical Formula 4]

[0061]

[0062] In Chemical Formula 4, L1 and L2 may each independently be an alkylene group or an alkylidene group. In Chemical Formula 4, the alkylene group and the alkylidene group may be equally applied to the aforementioned alkylene group and alkylidene group.

[0063] In chemical formula 4, m can be a number within the range of 1 to 500, 1 to 300, 1 to 100, 1 to 50, 1 to 30, 1 to 10, 1 to 5, 2 to 5, or 3 to 5.

[0064] [Chemical Formula 5]

[0065]

[0066] In chemical formula 5, Ar1 may be an arylene group, and L3 may be an alkylene group or an alkylidene group.

[0067] In chemical formula 5, n can be a number within the range of 1 to 500, 1 to 300, 1 to 100, 1 to 50, 1 to 30, 1 to 10, 1 to 5, 2 to 5, or 3 to 5.

[0068] In the above chemical formula 5, the alkylene group, alkylidene group and arylene group can be equally applied to the above-described alkylene group, alkylidene group and arylene group.

[0069] For example, the acid-modified biodegradable polyester may be a compound represented by any one of chemical formulas 6 to 9.

[0070] [Chemical Formula 6]

[0071]

[0072] In chemical formula 6, L4, L5, and L6 can each independently be an alkylene group, and Ar2 can be an arylene group. The alkylene group and arylene group of chemical formula 6 may be equally applied to the aforementioned alkylene group and arylene group.

[0073] In chemical formula 6, a and b can each independently be a number within the range of 1 to 500, 1 to 300, 1 to 100, 1 to 50, 1 to 30, 1 to 10, 1 to 5, 2 to 5, or 3 to 5.

[0074] [Chemical Formula 7]

[0075]

[0076] In chemical formula 7, L7, L8, and L9 can each independently be an alkylene group, and Ar3 can be an arylene group. The alkylene group and arylene group of chemical formula 7 may be equally applied to the aforementioned alkylene group and arylene group.

[0077] In chemical formula 7, c and d can each independently be a number within the range of 1 to 500, 1 to 300, 1 to 100, 1 to 50, 1 to 30, 1 to 10, 1 to 5, 2 to 5, or 3 to 5.

[0078] [Chemical Formula 8]

[0079]

[0080] In Chemical Formula 8, L4, L5, and L6 can each independently be an alkylene group, and Ar2 can be an arylene group. The alkylene group and arylene group of Chemical Formula 8 may be equally applied to the aforementioned alkylene group and arylene group.

[0081] In chemical formula 8, a and b can each independently be a number within the range of 1 to 500, 1 to 300, 1 to 100, 1 to 50, 1 to 30, 1 to 10, 1 to 5, 2 to 5, or 3 to 5.

[0082] [Chemical Formula 9]

[0083]

[0084] In chemical formula 9, L7, L8, and L9 can each independently be an alkylene group, and Ar3 can be an arylene group. The alkylene group and arylene group of chemical formula 9 can be equally applied to the aforementioned alkylene group and arylene group.

[0085] In chemical formula 9, c and d can each independently be a number within the range of 1 to 500, 1 to 300, 1 to 100, 1 to 50, 1 to 30, 1 to 10, 1 to 5, 2 to 5, or 3 to 5.

[0086] The copolymer represented by the above chemical formulas 6 to 9 may be a random copolymer or a block copolymer.

[0087] The above acid-modified biodegradable polyester can be produced, for example, by reacting maleic acid and / or maleic anhydride with a biodegradable polyester. By controlling the content of maleic acid and / or maleic anhydride, the content of the polyester, the reaction temperature, the reaction time, the type and content of the additive, etc., the acid-modified biodegradable polyester can be produced, and the weight average molecular weight, structure, and / or viscosity, etc. of the acid-modified biodegradable polyester can be controlled.

[0088] The above composition can ensure excellent compatibility by including the acid-modified biodegradable polyester together with the above-described acid-modified biodegradable polyester and pulp. Since the acid-modified biodegradable polyester is hydrophobic and the pulp is hydrophilic, it is difficult to uniformly mix the acid-modified biodegradable polyester and the pulp. Therefore, the above composition can ensure excellent compatibility by including the above-described acid-modified biodegradable polyester, thereby enabling the dispersion phase of the pulp to be uniformly and densely distributed on the matrix of the acid-modified biodegradable polyester, and strengthening the adhesive force at the interface between the acid-modified biodegradable polyester and the pulp.

[0089] In order to secure the desired properties such as compatibility and tensile properties, the content of each component included in the composition can be adjusted.

[0090] For example, the ratio of the acid-unmodified biodegradable polyester in the composition can be controlled. The lower limit of the ratio of the weight of the acid-unmodified biodegradable polyester to the total weight of the composition can be about 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, or 75 wt%, and the upper limit can be about 90 wt%, 80 wt%, 70 wt%, or 60 wt%. The ratio can be within a range that is equal to or greater than any one of the lower limits described above; or within a range that is equal to or less than any one of the upper limits described above; or within a range that is equal to or greater than any one of the lower limits described above and equal to or less than any one of the upper limits described above. When the ratio of the acid-unmodified biodegradable polyester is within the above range, excellent elongation, Young's modulus, and tensile strength can be secured.

[0091] For example, the proportion of pulp in the composition can be adjusted. For example, the lower limit of the content of the pulp relative to 100 parts by weight of the acid-unmodified biodegradable polyester can be about 10 parts by weight, 20 parts by weight, 30 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, 60 parts by weight, or 65 parts by weight, and the upper limit can be about 200 parts by weight, 100 parts by weight, 80 parts by weight, 70 parts by weight, 60 parts by weight, 50 parts by weight, 45 parts by weight, 40 parts by weight, 35 parts by weight, 30 parts by weight, or 25 parts by weight. The proportion can be within a range that is equal to or greater than any one of the lower limits described above; or within a range that is equal to or less than any one of the upper limits described above; Or, it may be within a range that is equal to or greater than any one of the lower limits described above, and equal to or less than any one of the upper limits described above. When pulp is included in the above ratio, the processability of the acid-unmodified biodegradable polyester can be improved and an excellent biodegradation rate can be secured.

[0092] For example, the content of the acid-modified biodegradable polyester in the composition can be adjusted. For example, the lower limit of the content of the acid-modified biodegradable polyester relative to 100 parts by weight of the acid-unmodified biodegradable polyester can be about 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, or 8 parts by weight, and the upper limit can be about 30 parts by weight, 25 parts by weight, 20 parts by weight, 15 parts by weight, 13 parts by weight, 11 parts by weight, 10 parts by weight, 9 parts by weight, 8 parts by weight, or 7 parts by weight. The ratio can be within a range that is equal to or greater than any one of the lower limits described above; or within a range that is equal to or less than any one of the upper limits described above; Or it may be within a range that is equal to or greater than any one of the lower limits described above, and equal to or less than any one of the upper limits described above. If the ratio of the acid-modified biodegradable polyester is too low, the compatibility between the acid-unmodified biodegradable polyester and the pulp may be reduced, resulting in a deterioration of physical properties such as tensile strength, and if the ratio is too high, there is a problem that it is difficult to secure the desired viscosity value.

[0093] The above composition can exhibit an appropriate viscosity. For example, the upper limit of the complex viscosity at 150℃ and an angular frequency of 0.1 rad / s may be about 200,000 Pa·s, 150,000 Pa·s, 100,000 Pa·s, 90,000 Pa·s, 80,000 Pa·s, 70,000 Pa·s, 65,000 Pa·s, 60,000 Pa·s, 55,000 Pa·s, 50,000 Pa·s, 45,000 Pa·s, 40,000 Pa·s, 35,000 Pa·s, 30,000 Pa·s, 28,000 Pa·s or 26,000 Pa·s, and the lower limit may be about 25,000 Pa·s, It may be about 30,000 Pa·s, 40,000 Pa·s, 50,000 Pa·s, 60,000 Pa·s, 70,000 Pa·s, 80,000 Pa·s, 90,000 Pa·s or 94,000 Pa·s. The viscosity may be within a range that is less than or equal to any one of the upper limits described above; or within a range that is equal to or greater than any one of the lower limits described above and less than or equal to any one of the upper limits described above. The viscosity may be a value measured in the manner described in the present embodiment item “2. Complex viscosity.” When the viscosity at a low shear rate is within the above range, it may be advantageous for mixing, storage and preservation stability.

[0094] For example, the upper limit of the complex viscosity at 150℃ and an angular frequency of 10 rad / s may be about 100,000 Pa·s, 90,000 Pa·s, 80,000 Pa·s, 70,000 Pa·s, 60,000 Pa·s, 50,000 Pa·s, 40,000 Pa·s, 30,000 Pa·s, 20,000 Pa·s, 10,000 Pa·s or 9,000 Pa·s, and the lower limit may be about 5,000 Pa·s, 6,000 Pa·s, 7,000 Pa·s, 8,000 Pa·s, 10,000 Pa·s, 13,000 Pa·s, 15,000 Pa·s, It may be about 17,000 Pa·s, 19,000 Pa·s, or 20,000 Pa·s. The viscosity may be within a range that is less than or equal to any one of the upper limits described above; or within a range that is greater than or equal to any one of the lower limits described above and less than or equal to any one of the upper limits described above. The viscosity may be a value measured in the manner described in the present embodiment item "2. Complex viscosity."

[0095] For example, the upper limit of the complex viscosity of the composition at 150°C and an angular frequency of 100 rad / s may be about 60,000 Pa·s, 50,000 Pa·s, 40,000 Pa·s, 20,000 Pa·s, 10,000 Pa·s, 9,000 Pa·s, 8,000 Pa·s, 7,000 Pa·s, 6,500 Pa·s, 6,000 Pa·s, 5,500 Pa·s, 5,000 Pa·s, 4,500 Pa·s, 4,000 Pa·s or 3,500 Pa·s, and the lower limit may be about 3,000 Pa·s, 3,200 Pa·s, 4,000 Pa·s, 5,000 Pa·s, 6,000 Pa·s or 6,500 Pa·s. The viscosity may be within a range that is less than or equal to any one of the upper limits described above; or within a range that is greater than or equal to any one of the lower limits described above and less than or equal to any one of the upper limits described above. The viscosity may be a value measured in the manner described in item "2. Complex viscosity" of this embodiment. If the viscosity of the composition at a high shear rate is too low, shrinkage upon cooling during the injection molding process may not be uniform, which may cause a portion of the manufactured product to shrink or warp more, resulting in an error between the design dimensions and the actual dimensions of the product. In addition, if the viscosity is too high, the flow may be uneven within the mold, which may not completely fill the cavity, and may cause structural defects due to internal stress, etc. The composition of the present specification may have a viscosity within the above range, thereby ensuring excellent injection moldability, and allowing the injection molded product to exhibit uniform dimensions.

[0096] The composition may exhibit low residual stress. For example, the composition may have an RS(%) of Equation 1 below at a certain level or less.

[0097] [Formula 1]

[0098] RS(%) = 100 × (RS 10 / RS0)

[0099] In Equation 1, RS0 is the residual stress at the point where 30% strain is applied to the composition at 150°C, and RS 10 is the residual stress at 10 seconds after 30% strain is applied to the composition at 150°C. The RS 10 The units of RS0 are the same.

[0100] For example, the upper limit of the RS(%) value of the above formula 1 may be about 1%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, or 0.15%, and the lower limit may be about 0.01%, 0.05%, or 0.1%. The RS(%) of the formula 1 may be within a range that is less than or equal to any one of the upper limits described above; or within a range that is equal to or greater than any one of the lower limits described above and less than or equal to any one of the upper limits described above. The RS(%) may be a value measured in the manner described in the “3. Residual Stress Evaluation” of this embodiment. When the RS(%) is within the above range, excessive pressure is not required in the injection molding process, and the injection molded product may exhibit uniform dimensions.

[0101] The composition of the present disclosure may be a composition for injection molding or thermoforming. For example, the composition may be a composition for injection molding.

[0102] The present specification discloses an injection-molded article formed using the composition. For example, the injection-molded article can be manufactured using an extruded article of the composition.

[0103] As used herein, the term "extruded product" refers to a product manufactured through an injection molding process. For example, it may refer to a product formed by extruding the composition, injecting the extruded product into an injection mold, and then injection molding the product. For example, the extruded product may be in the form of a pellet.

[0104] The above-mentioned injection product may include an acid-modified biodegradable polyester, pulp, and an acid-modified biodegradable polyester.

[0105] The meaning of the above acid-modified biodegradable polyester, pulp and acid-modified biodegradable polyester corresponds to the same components included in the above-mentioned composition, and the description thereof applies equally.

[0106] The composition can evenly disperse pulp within the composition by including the acid-modified biodegradable polyester. Accordingly, extrudates of the composition and injection-molded articles formed from the extrudates can exhibit excellent tensile properties. For example, these tensile properties may refer to tensile properties measured for extrudates of the composition.

[0107] For example, an injection-molded article formed using an extrudate of the composition may exhibit excellent elongation. This elongation may refer to an elongation measured for an extrudate of the composition. For example, the lower limit of the elongation at break of the extrudate according to ASTM D638 may be about 100%, 110%, 120%, 130%, 140%, 150%, 160%, 170%, 180%, 190%, 200%, 210%, 220%, 230%, 240%, or 250%, and the upper limit may be about 1,000%, 800%, 600%, or 500%. The elongation is within a range equal to or greater than any one of the lower limits described above; Or, it may be within a range that is equal to or greater than any one of the lower limits described above, and equal to or less than any one of the upper limits described above. The elongation may be a value measured in the manner described in the item “1. Evaluation of tensile properties” of this embodiment.

[0108] For example, an injection-molded article formed using an extrudate of the composition may exhibit excellent tensile strength. This tensile strength may refer to a tensile strength measured for an extrudate of the composition. For example, the lower limit of the tensile strength of the extrudate according to ASTM D638 may be about 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, 10 MPa, 11 MPa, 12 MPa, 13 MPa, 14 MPa, 15 MPa, or 16 MPa, and the upper limit may be about 100 MPa. The strength may be within a range that is equal to or greater than any one of the lower limits described above; or within a range that is equal to or greater than any one of the lower limits described above and equal to or less than any one of the upper limits described above. The above tensile strength may be a value measured in the manner described in item “1. Evaluation of tensile properties” of this embodiment.

[0109] For example, an injection-molded article formed using an extrudate of the above composition can exhibit excellent Young's modulus. For example, the lower limit of the Young's modulus according to ASTM D638 can be about 0.1 GPa, 0.2 GPa, 0.3 GPa, or 0.4 GPa, and the upper limit can be about 10 GPa, 9 GPa, 8 GPa, 7 GPa, 6 GPa, 5 GPa, 4 GPa, 3 GPa, 2 GPa, 1 GPa, or 0.5 GPa. The Young's modulus can be within a range that is equal to or greater than any one of the lower limits described above; or within a range that is equal to or greater than any one of the lower limits described above and equal to or less than any one of the upper limits described above. The Young's modulus can be a value measured by the method described in the present embodiment item "1. Evaluation of tensile properties."

[0110] The present specification discloses a method for manufacturing an injection molded article.

[0111] For example, the manufacturing method may include a step of reacting an acid-modified biodegradable polyester with maleic acid to produce an acid-modified biodegradable polyester; a step of mixing an acid-modified biodegradable polyester, pulp, and the acid-modified biodegradable polyester; a step of extruding the mixture; and a step of injection-molding the extrudate to produce an injection-molded product.

[0112] For example, through the step of reacting the above-mentioned acid-modified biodegradable polyester and maleic acid, the hydroxyl group at the terminal of the acid-modified biodegradable polyester and the carboxyl group of maleic acid can react to form an ester bond. The compound in which such an ester bond is formed can be the above-mentioned acid-modified biodegradable polyester.

[0113] The ratio of the maleic acid and the acid-unmodified biodegradable polyester can be controlled. For example, the lower limit of the ratio of maleic acid to 100 parts by weight of the acid-unmodified biodegradable polyester can be about 0.1 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, or 10 parts by weight, and the upper limit can be about 100 parts by weight, 90 parts by weight, 80 parts by weight, 70 parts by weight, 60 parts by weight, 50 parts by weight, 40 parts by weight, 30 parts by weight, 20 parts by weight, 15 parts by weight, or 10 parts by weight. The ratio can be within a range that is equal to or greater than any one of the lower limits described above; or within a range that is equal to or less than any one of the upper limits described above; Or, it may be within a range that is equal to or greater than any one of the lower limits described above, and equal to or less than any one of the upper limits described above.

[0114] In order to secure appropriate reactivity between the acid-unmodified biodegradable polyester and maleic acid, the reaction temperature of the acid-unmodified biodegradable polyester and maleic acid can be controlled. For example, the lower limit of the temperature can be about 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, or 160°C, and the upper limit can be about 300°C, 250°C, 200°C, 190°C, 180°C, 170°C, or 160°C. The temperature can be within a range that is equal to or greater than any one of the lower limits described above; or within a range that is equal to or less than any one of the upper limits described above; Or, it may be within a range that is equal to or greater than any one of the lower limits described above, and equal to or less than any one of the upper limits described above.

[0115] In order to secure appropriate reactivity and economic feasibility of the acid-unmodified biodegradable polyester and maleic acid, the reaction time of the acid-unmodified biodegradable polyester and maleic acid can be controlled. For example, the lower limit of the time can be about 10 minutes, 15 minutes, 20 minutes, 25 minutes, or 30 minutes, and the upper limit can be about 200 minutes, 150 minutes, 100 minutes, 80 minutes, 70 minutes, 60 minutes, 50 minutes, 40 minutes, or 30 minutes. The time can be within a range that is equal to or greater than any one of the lower limits described above; within a range that is equal to or less than any one of the upper limits described above; or within a range that is equal to or greater than any one of the lower limits described above and equal to or less than any one of the upper limits described above.

[0116] In the step of preparing a mixture by mixing the above acid-modified biodegradable polyester, pulp and acid-modified biodegradable polyester, the mixing can be performed by hand mixing, using a mixer, and / or mixing inside an extruder.

[0117] The above manufacturing method may include a step of extruding the mixture.

[0118] The extrusion can be performed within a predetermined temperature range. For example, the lower limit of the extrusion temperature can be about 100°C, 110°C, 120°C, 130°C, or 140°C, and the upper limit can be about 180°C, 170°C, 160°C, 150°C, or 140°C. The temperature can be within a range that is equal to or greater than any one of the lower limits described above; or within a range that is equal to or less than any one of the upper limits described above; or within a range that is equal to or greater than any one of the lower limits described above and equal to or less than any one of the upper limits described above.

[0119] The above manufacturing method may include a step of forming an injection molded article.

[0120] For example, a pellet (extrudate) manufactured through extrusion can be injected into an injection mold to form an injection molded product. The mold temperature, injection pressure, injection speed, holding pressure and holding time, cooling time, injection time, etc. of the injection molding can be appropriately adjusted depending on the desired product.

[0121] The extrudate of the above composition exhibits excellent injection moldability, and the injection molded product using the composition may have small dimensional deviation.

[0122] The present specification discloses compositions and uses thereof.

[0123] The present disclosure discloses a composition manufactured from a biodegradable material, which exhibits improved tensile properties while being manufactured at a low cost.

[0124] The present specification discloses a composition having an appropriate viscosity, which can minimize dimensional deviation of an injection molded product and improve shape precision during injection molding.

[0125] The present specification discloses an injection molded article formed using the above composition.

[0126] Figure 1 shows the viscosity measurement results of examples and comparative examples.

[0127] Figure 2 shows the results of residual stress evaluation of examples and comparative examples.

[0128] Figure 3 shows the SEM analysis results of the example.

[0129] Figure 4 shows the SEM analysis results of a comparative example.

[0130] The compositions and the like disclosed in this specification are specifically described through the following examples or comparative examples, but the scope of the compositions and the like is not limited by the following examples.

[0131]

[0132] 1. Tensile property evaluation

[0133] Young's modulus, tensile strength, and elongation at break were evaluated according to ASTM D638. Specimens were prepared according to ASTM D638 using pellets from the examples or comparative examples. At room temperature (approximately 25°C), both ends of the specimen were clamped in the clamps of a UTM (Universal Testing Machine). One clamp was fixed, and the other clamp was pulled in the machine direction at a speed of approximately 10 mm / sec to obtain a stress-strain curve. Based on this curve, the Young's modulus, tensile strength, and elongation at break were measured. The results of the tensile property evaluation are shown in Table 1.

[0134]

[0135] 2. Complex viscosity

[0136] The complex viscosity according to the angular frequency of the composition was obtained at 150°C using the dynamic frequency sweep method using an advanced rheometric expansion system (ARES). The dynamic frequency sweep was measured using a 25 mm parallel plate in the form of a disk, and was measured in the angular frequency range of 0.1 rad / s to 100 rad / s. The viscosity measurement results are shown in Fig. 1.

[0137]

[0138] 3. Residual stress evaluation

[0139] After applying 30% strain to the composition at 150°C, the change in residual stress was measured for 30 seconds. The residual stress was measured using a Discovery Hybrid Rheometer (DHR) from TA Instruments. The composition was sufficiently loaded between upper and lower plates with a diameter of 25 mm, melted at 150°C, and the gap was fixed at 1 mm for measurement. Based on the measured residual stress data, the residual stress ratio (RS(%)) was evaluated according to Equation 1 below. The results of the residual stress ratio (RS(%)) evaluation are shown in Table 3.

[0140] [Formula 1]

[0141] RS(%) = 100 × (RS 10 / RS0)

[0142] In Equation 1, RS0 is the residual stress at the point where 30% strain is applied to the composition at 150°C, and RS 10 is the residual stress at 10 seconds after 30% strain is applied to the polymer composition at 150°C, and the RS 10 The units of RS0 are the same.

[0143]

[0144] 4. SEM (Scanning Electron Microscope) Measurement

[0145] The pellet was etched at 80°C for 15 minutes using a 25% NaOH solution. Subsequently, a platinum (Pt) coating system (Hitachi E-1030) was used for sputtering for 30 seconds to coat the surface of the pellet with platinum (Pt) to a thickness of approximately 5 nm, thereby preparing a sample.

[0146] YAG BSE Detector and Oxford 100 mm 2The surface image of the sample was observed using a Field Emission Scanning Electron Microscope (FE-SEM) equipped with an EDS detector (Hitachi, S-4800). The acceleration voltage was 2 kV and the working distance was 8 mm. The SEM measurement results are shown in Figs. 3 and 4.

[0147]

[0148] Manufacturing Example 1. Manufacturing of acid-modified PBAT

[0149] 100 g of PBAT (Polybutylene adipate terephthalate) (SOLTECH, Solpol 1000N) and 10 g of maleic acid were added to an internal mixer and reacted at 160°C and 50 rpm for 30 minutes.

[0150] The above PBAT had a density (ASTM D792) of about 1.26 g / ml, a Melt Flow Index (MFI) (190°C, 2160g) (ISO1133) of about 3±1.5 g / 10 min, a melting point (ASTM D2117) of about 120°C, an acid value (ASTM D974) of 0.9 mg-KOH / g or less, and a glass transition temperature (ASTM D2117) of about -28°C.

[0151] According to the above reaction, the terminal hydroxyl group (-OH) of the PBAT and maleic acid undergo an esterification reaction, and as a result, PBAT is obtained in which maleic acid is bonded to the terminal hydroxyl group (-OH) of the PBAT by an ester bond, and in this specification, the PBAT is named acid-modified PBAT.

[0152]

[0153] Manufacturing Example 2. Manufacturing of thermoplastic starch

[0154] 225 g of corn starch and 75 g of glycerol, based on dry weight, were mixed in a mixer and then placed in an extruder for compounding. The temperature of the extruder was set to 80 to 150°C, the screw speed was set to 150 rpm, and the extruded strands were pulverized using a pelletizer to produce thermoplastic starch pellets.

[0155]

[0156] Example 1.

[0157] 80 g of PBAT (Polybutylene adipate terephthalate) (SOLTECH, Solpol 1000N) (acid-unmodified PBAT), 20 g of pulp, and 5 g of the acid-modified PBAT of Manufacturing Example 1 were placed in an extruder on a dry weight basis, and a composition was prepared through a mixing process. The temperature of the extruder was set to 140°C, and the screw speed was set to 150 rpm.

[0158] For the above pulp, flake-shaped pulp of approximately 5 mm in size supplied by Mulim Paper was used without any separate processing.

[0159] The above PBAT had a density (ASTM D792) of about 1.26 g / ml, a Melt Flow Index (MFI) (190°C, 2160g) (ISO1133) of about 3±1.5 g / 10 min, a melting point (ASTM D2117) of about 120°C, an acid value (ASTM D974) of 0.9 mg-KOH / g or less, and a glass transition temperature (ASTM D2117) of about -28°C.

[0160] The above composition was extruded to obtain a strand, which was cooled by passing it through an air-cooled conveyor belt, and then cut into 3 mm to 5 mm lengths using a pelletizer to produce pellets.

[0161]

[0162] Example 2.

[0163] A composition and pellets were prepared in the same manner as in Example 1, except that the amount of unmodified PBAT was changed to 60 g and the amount of pulp was changed to 40 g.

[0164]

[0165] Comparative Example 1.

[0166] A composition and pellets were prepared in the same manner as in Example 1, except that the acid-modified PBAT of Manufacturing Example 1 was not used.

[0167]

[0168] Comparative Example 2.

[0169] A composition and pellets were prepared in the same manner as in Example 2, except that the acid-modified PBAT of Manufacturing Example 1 was not used.

[0170]

[0171] Comparative Example 3.

[0172] 750 g of polybutylene adipate terephthalate (PBAT) (Soltech, Solpol 1000N) (unmodified PBAT) on a dry weight basis, 250 g of the thermoplastic starch of Preparation Example 2, and 50 g of the acid-modified PBAT of Preparation Example 1 were hand-mixed and then placed into an extruder for compounding. The temperature range of the extruder was 120 to 150°C, and the screw speed was set to 150 rpm. The extruded strands were cut using a pelletizer to produce pellets.

[0173]

[0174] The results of the physical property measurements for the above examples and comparative examples are summarized and described in Tables 1 to 3 below.

[0175]

[0176] Young's modulus (GPa) Tensile strength (MPa) Elongation at break (%) Example 10.23 16.9 > 250 Example 20.42 16.9 113.43 Comparative example 10.33 198 8.53 Comparative example 20.67 25.9 16.17 Comparative example 30.0 9 28.1 > 450

[0177] Complex viscosity (Pa·s) at each frequency of 150°C and 0.1 rad / s Complex viscosity (Pa·s) at each frequency of 150°C and 100 rad / s Example 126,0003,340 Example 294,0006,500 Comparative Example 1220,0006,740 Comparative Example 21,270,00020,300 Comparative Example 314,0002,280

[0178] Ratio of residual stress (RS(%))Example 10.11Example 20.42Comparative Example 11.43Comparative Example 23.84

[0179] The composition of the embodiment includes an acid-modified biodegradable polyester, and since the acid-modified biodegradable polyester exhibits hydrophilicity and hydrophobicity, it can play a role in allowing the acid-unmodified biodegradable polyester and pulp to be well mixed.

[0180] Accordingly, it can be confirmed that the pulp is evenly distributed and that the pulp is distributed in the form of a small sphere and forms a domain (Fig. 3).

[0181] In addition, it can be seen that the composition of the example has excellent compatibility between the acid-unmodified biodegradable polyester and the pulp, so that the extrudate exhibits excellent elongation and a certain level or higher of Young's modulus and tensile strength.

[0182] In addition, the composition of the embodiment has a viscosity within an appropriate range, has excellent injection processability, and has low residual stress, so that it can minimize dimensional deviation of the injection-molded product and improve shape precision.

[0183] On the other hand, the compositions of Comparative Examples 1 and 2 contained pulp, so a certain level of Young's modulus and tensile strength was secured, but since they did not contain acid-modified biodegradable polyester, the compatibility between the acid-unmodified biodegradable polyester and the pulp was low, and thus breakage occurred quickly, resulting in a decrease in elongation. In addition, it can be confirmed that the pulp was not evenly distributed, so that the thick fiber form of the pulp remained (Fig. 4).

[0184] In addition, the compositions of Comparative Examples 1 and 2 have high viscosity, which causes uneven flow within the mold during injection molding, preventing the cavity from being completely filled, and high residual stress, which may cause structural defects such as dimensional deviations in the injection-molded product.

[0185] The composition of Comparative Example 3 has a high elongation due to the soft nature of the starch and a tensile strength above a certain level, but not only is the strength such as Young's modulus low, but the viscosity is also very low, so that shrinkage is not uniform when cooling during the injection molding process, and some of the manufactured product may shrink or warp more, causing an error between the design dimensions and the actual dimensions of the product, making it unsuitable for the injection molding process.

Claims

1. Acid-modified biodegradable polyester; pulp; and acid-modified biodegradable polyester, The complex viscosity at 150℃ and angular frequency of 100 rad / s is 3,000 Pa·s or more, A composition having a complex viscosity of 200,000 Pa·s or less at 150°C and a frequency of 0.1 rad / s.

2. In the first paragraph, a composition having RS(%) of the following formula 1 of 1% or less: [Formula 1] RS(%) = 100 × (RS 10 / RS0) In Equation 1, RS0 is the residual stress at the point where 30% strain is applied to the composition at 150°C, and RS 10 is the residual stress at 10 seconds after 30% strain was applied to the composition at 150°C.

3. In the first paragraph, the biodegradable polyester is a composition comprising a unit of the following chemical formula 1 and a unit of the following chemical formula 2: [Chemical Formula 1] In chemical formula 1, L1 and L2 are each independently an alkylene group or an alkylidene group: [Chemical Formula 2] In chemical formula 2, Ar1 is an arylene group, and L3 is an alkylene group or alkylidene group.

4. In the first paragraph, the acid-modified biodegradable polyester is a composition comprising a functional group of the following chemical formula 3 at the terminal: [Chemical Formula 3] 5. In the first paragraph, the acid-modified biodegradable polyester is a composition comprising a unit of the following chemical formula 4 or 5 at the terminal: [Chemical Formula 4] In chemical formula 4, L1 and L2 are each independently an alkylene group or an alkylidene group, and m is a number in the range of 1 to 500: [Chemical Formula 5] In chemical formula 5, Ar1 is an arylene group, L3 is an alkylene group or alkylidene group, and n is a number in the range of 1 to 500.

6. In the first paragraph, the acid-modified biodegradable polyester is a composition represented by any one of the following chemical formulas 6 to 9: [Chemical Formula 6] In chemical formula 6, L4, L5 and L6 are each independently an alkylene group having 2 to 20 carbon atoms, Ar2 is an arylene group, and a and b are each independently a number from 1 to 500: [Chemical Formula 7] In chemical formula 7, L7, L8 and L9 are each independently an alkylene group having 2 to 20 carbon atoms, Ar3 is an arylene group, and c and d are each independently a number from 1 to 500: [Chemical Formula 8] In chemical formula 8, L4, L5 and L6 are each independently an alkylene group having 2 to 20 carbon atoms, Ar2 is an arylene group, and a and b are each independently a number from 1 to 500: [Chemical Formula 9] In chemical formula 9, L7, L8 and L9 are each independently an alkylene group having 2 to 20 carbon atoms, Ar3 is an arylene group, and c and d are each independently a number from 1 to 500.

7. A composition comprising 30 to 90 wt% of an acid-modified biodegradable polyester according to claim 1.

8. A composition comprising 1 to 30 parts by weight of an acid-modified biodegradable polyester relative to 100 parts by weight of an acid-unmodified biodegradable polyester in the first paragraph.

9. A composition comprising 10 to 200 parts by weight of pulp relative to 100 parts by weight of acid-modified biodegradable polyester according to claim 1.

10. A composition according to claim 1, wherein the pulp is in the form of flakes.

11. In the first paragraph, the composition is a composition for injection molding or thermoforming.

12. An injection molded article formed using the extrudate of the composition of paragraph 1.

13. An injection-molded article in accordance with paragraph 12, wherein the elongation at break according to ASTM D638 of the extruded article is 100% or more.

14. An injection-molded article in accordance with paragraph 12, wherein the tensile strength of the extruded article according to ASTM D638 is 5 MPa or more.

15. An injection-molded article in claim 12, wherein the Young's Modulus according to ASTM D638 of the extruded article is 0.1 GPa or more.

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