107 results about "D-Lactic Acid" patented technology

This invention provides a polylactic acid resin composition in which stereocomplex crystals of poly-L-lactic acid and poly-D-lactic acid can be selectively crystallized to obtain polylactic acid having a sufficiently high speed of crystallization and a sufficiently high ratio of stereocomplex crystal and a molded article thereof obtained via melt molding and crystallization of the same. Such polylactic acid resin composition comprises polylactic acid capable of generating stereocomplex crystallization and an aromatic urea compound represented by formula (1):

wherein R¹ represents an alkylene group having 1 to 10 carbon atoms; R² represents an alkyl group having 1 to 25 carbon atoms; and m is an integer between 1 to 6.

Disclosed is a biaxially stretched polylactic acid multilayer film and the use thereof as packaging film. The gist of the biaxially stretched polylactic acid multilayer film resides in the construction wherein a substrate layer (1) of the biaxially stretched film comprised of polylactic acid (A) has been laminated on at least one surface thereof with a coating layer (II) of an aliphatic polyester composition (D) comprised of 97˜5% by weight of an aliphatic polyester copolymer (B) having a melting point (Tm) of 80˜120° C., a crystallizing temperature (Tc) of 35˜75° C. and a difference of (Tm)−(Tc) within the range of 35˜55° C. and comprising an aliphatic or alicyclic dicarboxylic acid component (b1), an aliphatic or alicyclic dihydroxyl compound component (b2) and a difunctional aliphatic hydroxycarboxylic acid component (b3) and 3˜95% by weight of a polylactic acid copolymer (C) containing 7˜30% by weight of D-lactic acid, a total of the ingredients (B) and (C) being 100% by weight.

The biodegradable sheet is a laminated sheet including at least two layers. Each of the layers forming the laminated sheet is a resin composition comprising 75 to 25% by mass of a polylactic acid resin, and 25 to 75% by mass of a polyester resin having a glass transition temperature not exceeding 0 degrees C. and a melting point higher than the glass transition temperature of the polylactic acid resin, and not exceeding the melting point of the polylactic acid resin, based on 100 mass percent of the total amount of the polylactic acid resin and the polyester resin. The D-lactic acid content of the polylactic acid resin contained in one layer, and the D-lactic acid content of the polylactic acid resin in the other layer are determined to satisfy a predetermined relationship. The laminated sheet is subjected to crystallization treatment.

The present invention provide a heat-shrinkable film consisting of a layer or comprising at least one layer, wherein the layer is made of a mixed resin containing a polylactic acid resin and a polyolefin resin as the main components, wherein mass ratio of the polylactic acid resin and the polyolefin resin is 95/5 to 50/50 by mass, the polylactic acid resin being a copolymer of D-lactic acid and L-lactic acid or a mixed resin of the copolymer, wherein D/L ratio of D-lactic acid and L-lactic acid is 3/97 to 15/85 or 85/15 to 97/3, the storage elastic modulus (E′) of the polyolefin resin or the soft acrylic resin at 20 degree C. being 100 MPa or less as measured at an oscillation frequency of 10 Hz and a strain of 0.1%, the film being stretched in at least one direction, and the heat shrinkage ratio of the film in the main shrinking direction being 20% or more as measured after the film is immersed in hot water of 80 degree C. for 10 seconds.

The heat-shrinkable film exhibits excellent heat-shrinkable property, impact resistance, transparency, mechanical property, and shrink finishing quality; it is applicable to shrinkable packing, shrinkable bond-packing, shrinkable label and the like.

The invention discloses a polylactic resin composition with high heat resistance and high flexibility and a preparation method of the composition, solving the problem that polylactic resin with high heat resistance and high flexibility does not exist in the prior art. The polylactic resin composition consists of the following components in parts by weight: 50 to 99.5 weight parts of poly-L-lactic acid homopolymer and 0.5 to 50 weight parts of poly-D-lactic acid copolymer, wherein the poly-D-lactic acid copolymer is prepared from poly-D-lactic acid and a polymer with a flexible chain structure. The invention also provides the preparation method of the polylactic resin composition with high heat resistance and high flexibility. The preparation method is simple and suitable for industrialized production; and the prepared polylactic resin composition has high flexibility and heat resistance, the elongation at break reaches 16 percent, the notch impact strength reaches 12.2kJ/m<2>, and the vicat softening temperature reaches 113 DEG C.

A stretch mold container of the present invention is obtained by draw-forming a resin composition containing a poly-L-lactic acid (A) and a poly-D-lactic acid (B) at a molar ratio A:B in a range of 95:5 to 60:40, and has an amount of heat shrinkage of 5.0% or less under heat treatment conditions of 65° C.×24 hours. Despite of being made from the polylactic acids, the stretch mold container exhibits excellent heat resistance.

A resin composition comprising an aromatic polyester having a butylene terephthalate skeleton as the main constituent unit (component A), polylactic acid comprising poly(L-lactic acid) and poly(D-lactic acid) (component B), and a modifier (component C), wherein

• • the resin composition has (i) a crystal melting peak of stereocomplex-phase polylactic acid at 190° C. or higher in differential scanning calorimeter measurement, (ii) a biomass ratio of not less than 50%, (iii) a notched Izod impact strength of 4 to 15 kJ/m² and (iv) a flexural modulus of 2.5 to 6 GPa.

The resin composition provides a molded article having excellent impact resistance and stiffness. The resin composition has a biomass ratio of not less than 50%. The resin composition has a low moisture absorptivity, hydrolysis resistance and high-speed moldability. The resin composition provides a molded article having excellent heat resistance.

The invention discloses a preparation method of a food-grade full-degradable high-temperature-resistant polylactic acid composite material, and belongs to the field of biodegradable high polymer materials. The composite material comprises, by weight, 100 parts of poly-l-lactic acid (PLLA), 1-10 parts of poly-d-lactic acid (PDLA) and 0.5-1 part of functional additives. Compared with traditional petroleum-based high polymer materials, the composite material has the advantages of being easy to degrade and renewable; compared with common polylactic acid, the composite material has excellent heat resistance. Thus, the polylactic acid composite material can be applied to high-temperature-resistant food packages.

This invention provides a polynucleotide that encodes a protein having lactate dehydrogenase activity and such protein that can be used for producing D-lactic acid. This polynucleotide has the nucleotide sequence as shown in SEQ ID NO: 1 (a), and it hybridizes under stringent conditions with a probe comprising all or part of the nucleotide sequence as shown in SEQ ID NO: 1 or a complementary strand thereof and encodes a protein having D-lactate dehydrogenase activity (b).

The invention discloses sporolactobacillus terrae HKM-1 and a method for producing D-lactic acid therefrom through fermentation. The sporolactobacillus terrae HKM-1 is collected in China Center for Type Culture Collection with the collection number CCTCC NO: M2013389, and also collected in DSMZ (Deutsche Sammlung von Mikroorganismen und Zellkulturen) with the collection number DSM No.27555. HKM-1 can be used for producing D-lactic acid by using a cheap nitrogen source, namely dry powder of corn steep liquor; the highest fermentation yield of D-lactic acid is 197g/L, the corresponding fermentation period is only 47g, and the fermentation production capacity reaches up to 4.19g/L/h which is far higher than the value publically reported already at present; the strain HKM-1 is stable in high yield performance and capable of producing high-optical purity D-lactic acid, and the optical purity of the produced D-lactic acid is 99.9%; raw materials for fermentation are wide in source and low in cost, and the fermentation state is between anaerobic and micro-aerobic; the method provided by the invention can be used for producing the D-lactic acid through fermentation, and is capable of saving cost and improving production efficiency and also has important industrial application value.

The invention relates to a polylactic acid block copolymer, which solves the problems that current method is hard to prepare the polylactic acid block copolymer with high-melting point polyester. The polylactic acid block copolymer is a two-block copolymer which is shown as A-b-B, wherein A is a single-end hydroxyl aromatic polyester block, and B is a polylactic acid block. The polylactic acid block is one or more of a poly-L-lactic acid block, a poly-D-lactic acid block and a poly-DL lactic acid block. The polylactic acid block copolymer is prepared by the following step of: adopting an organic solvent which can dissolve reactants of single-end hydroxyl aromatic polyester and lactide to be a reaction medium, tin salt as a catalyst, and the single-end hydroxyl aromatic polyester as an initiator to initiate the ring opening polymerization of lactide. With the adoption of the polylactic acid block copolymer, the polymerizing temperature can be controlled to reach a scope in which polylactic acid and lactide cannot be degraded, and the racemization cannot be carried out, so that the generation of transesterification can be effectively inhibited, the regularity of the chain section can be ensured, and the block copolymers of polyester and the polylactic acid can be successfully prepared, including aromatic polyester with the high-melting point.

The invention discloses radix sophorae flavescentis residue polysaccharide synbiotics and a preparation method and application thereof. The radix sophorae flavescentis residue polysaccharide synbiotics is obtained by using radix sophorae flavescentis residue polysaccharide as a unique raw material through fermentation of lactobacillus plantarum. An experiment result shows that the prepared synbiotics is capable of remarkably improving a mouse visceral index and mouse intestinal tract digestive enzyme activity, keeping integrity and permeability of an intestinal tract mucous membrane, maintaining an intestinal tract barrier function, reducing levels of toxin, diamine oxidase, D-lactic acid and an inflammatory factor in a body, and through improving mouse intestinal tract bacterial diversityand flora composition structure, promoting growth of beneficial bacteria, reducing a number of harmful bacteria, regulating animal intestinal microecology, and reinforcing digestive ability and immunocompetence of an animal, and has an important application value.