JP4158800B2 - Aliphatic polyester cup - Google Patents

Description

  The present invention relates to an aliphatic polyester cup having improved mechanical strength anisotropy.

  In recent years, the amount of solid waste discharged from cities has become increasingly large and is approaching the limit of its waste disposal capacity. Plastic is always pointed out as one of the causes of this solid waste.

  As an ideal solution for plastic waste, degradable plastic that disappears in the natural environment has attracted attention. The degradable plastic includes a photodegradable plastic in which a molecular chain of a polymer is cleaved by ultraviolet rays, and a biodegradable plastic that is disintegrated by the action of an enzyme released by bacteria and fungi outside the body.

  However, in the case of a photodegradable plastic, an effect cannot be expected in the soil burying treatment, and there is a risk of environmental pollution due to a decomposition product, and thus there is a great expectation for the biodegradable plastic.

  Conventional biodegradable plastics include aliphatic polyesters such as polyhydroxybutyrate (PHA), random copolymers of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV), poly (ε-caprolactone). (PCL), polybutylene succinate (PBS), polybutylene succinate adipate (PBAS), polylactic acid (PLLA) and the like are known.

  However, although these aliphatic polyesters are excellent in terms of harmony with the environment such as biodegradability, they still have problems that must be solved in terms of moldability. As an example, aliphatic polyester has a problem that the melt property of a resin is inferior, and molding such as direct blow, injection stretch molding, and thermoform molding of a sheet is difficult. For this reason, the improvement of the melt tension by adding an inorganic filler (Patent Document 1) and the increase in the molecular weight by chain length extension using a diisocyanate, a diepoxy compound, or an acid anhydride (Patent Document 2) have been proposed. In addition, the aliphatic polyester can generally improve the material strength by processing by stretch molding.

JP-A-5-289623 JP-A-7-205278

  As in the case of ordinary plastics, aliphatic polyester improves mechanical strength such as yield point strength and elastic modulus by stretching. However, when an aliphatic polyester is biaxially stretch-molded, the resulting stretch-molded product has anisotropy in mechanical strength.

  For example, in the biaxially stretched molded product of aromatic polyester and polyethylene terephthalate (PET), the yield point strength in the stretching direction, that is, the machine direction (MD) and the transverse direction (TD), and the yield in the direction of 45 degrees from MD and TD. Although the point strength is almost equal, the aliphatic polyester such as polylactic acid has a yield point strength of 45 degrees from the MD and TD directions, that is, the machine direction (MD) and the transverse direction (TD). It is lower than the yield point strength in the direction.

  As described above, the biaxially stretched molded article of the aliphatic polyester has anisotropy in mechanical strength, and the strength is lowered particularly in the direction of the stretched axis where the strength should be increased. Have a problem. For example, in a three-dimensional molded container such as a bottle or a cup, it is suitable that the stretching direction is the container axial direction and the container circumferential direction. In this case, the isotropic mechanical strength of the surface formed by the stretching axis is an important point for preventing buckling, cracking due to drop impact, and cracking due to expansion, contraction, and deformation. However, the strength of the biaxially stretched molded body of the aliphatic polyester does not achieve the intended purpose because the mechanical strength is different even in the direction in which the strength in the axial direction and the circumferential direction is in the direction of 45 degrees with the stretched axis. On the other hand, it is not practical to perform the stretching operation in a direction deviated by 45 degrees from the axial direction or circumferential direction of the container.

  Moreover, it was found that the biaxially stretched molded article having anisotropy in mechanical strength as described above often has a tendency to generate cracks during compression deformation as shown in the comparative example.

  Accordingly, an object of the present invention is to provide an aliphatic polyester cup having stable mechanical strength characteristics in which the above-mentioned mechanical strength anisotropy is eliminated or reduced in a biaxially stretched molded body formed from an aliphatic polyester. There is.

  According to the present invention, a resin sheet mainly composed of an aliphatic polyester is subjected to compression molding by variably controlling the stretching speed so that the initial stretching speed is large and the final stretching speed is small at a certain stretching temperature. A cup formed by plug-assist molding, which has a strength that can withstand 10% compression strain, is provided.

  According to the present invention, an aliphatic polyester is stretch-molded by performing a biaxial stretching operation in which a negative gradient is provided to a stretching speed at which the initial stretching speed is large and the final stretching speed is small at a certain stretching temperature. The region where the strength characteristics of the object satisfy the above formula (1), the anisotropy of the mechanical strength is eliminated or reduced, and the improvement of the anisotropy is the degree of orientation (Do) of 0.15 or more. To be achieved. The container made of the stretched molded article of the present invention is excellent in buckling resistance and drop impact resistance, and has an advantage that it is effectively prevented from cracking due to expansion / contraction and deformation. Furthermore, by forming a hard carbon film on the stretched molded article of aliphatic polyester by chemical vapor deposition (CVD), it is possible to improve gas permeability resistance and to suppress sorption of low molecular organic components. .

[Action]
In the present invention, the biaxial stretching of the aliphatic polyester preform is performed by stretch molding in which a negative gradient is provided to the stretching speed in which the initial stretching speed is increased and the final stretching speed is decreased. This is based on a novel finding that anisotropy can be eliminated or reduced.

  That is, in the present invention, the mechanical strength of the aliphatic polyester stretched molded article is changed by performing a biaxial stretching operation in which a negative gradient is provided to the stretching speed that increases the initial stretching speed and decreases the final stretching speed. This is important for eliminating or reducing the directivity. For example, when stretching is performed at a constant stretching speed, the stretching point yield strength in the stretching direction is compared to the yield point strength in the 45 degree direction (diagonal direction) in both cases where the stretching speed is large and small. And then it has declined. On the other hand, the yield point strength in the stretching direction is changed to the yield point strength in the diagonal direction by performing stretch molding with a negative gradient in the stretching speed that increases the initial stretching speed and decreases the final stretching speed. Can be greater than or equal to. As a result, it has become possible to eliminate the disadvantage that the strength in the stretching direction is lowered.

The stretched stretched aliphatic polyester product according to the present invention exhibits strength characteristics that satisfy the above formula (1). For this reason, the container made of the stretched molded article of the present invention has the advantages that it is excellent in buckling resistance and drop impact resistance, and cracks due to expansion and contraction and deformation are effectively prevented.
The stretched molded product according to the present invention has an orientation crystallinity (Do) defined by the above formula (2) of 0.15 or more, particularly 0.2 or more, because of its mechanical properties, transparency and heat resistance. This is preferable.

Usually, a thermoplastic polyester derived from a dibasic acid mainly composed of an aromatic carboxylic acid and a glycol can measure the crystallinity by orientation by the density method, and the measured density and crystallinity Is represented by the following formula (3).
Crystallinity _Xc = ([rho] _c / [rho]) * {([rho]-[rho] _am ) / ([rho] _{c- [} rho] _am )}} 100
(3)
In the formula, ρ is an n-heptane-carbon tetrachloride density gradient tube (manufactured by Ikeda Rika Co., Ltd.), the density of the sample measured at 20 ° C., ρ _am is the amorphous density (1.335 g / cm ³ ), and ρ _c is Crystal density (1.455 g / cm ³ ).

However, in the case of aliphatic polyesters, the density of both the amorphous sample and the highly oriented sample is almost constant, especially for polylactic acid, and the orientation crystallinity cannot be determined using the density method.
The inventors of the present invention have a peak area with a chemical shift of 100 to 300 ppm (carbonyl carbon region) when the aliphatic polyester is measured by ¹³ C wide NMR, and this peak area is closely related to the degree of orientation of the aliphatic polyester. It was found that the degree of orientation can be measured. That is, the area S of the NMR spectrum was determined for the stretched stretched aliphatic polyester, and then the peak area Sa of the NMR spectrum when measured in the same manner as described above for the amorphous powder of this sample was determined from the above formula (2). The orientation crystallinity (Do) is calculated. There is a 1: 1 correspondence between the orientation crystallinity (Do) thus determined and the draw ratio.

  FIG. 1 shows the relationship between the stretch ratio (axial stretch ratio, area stretch ratio) and the obtained oriented crystallinity (Do) for various stretched molded articles of aliphatic polyester. According to FIG. 1, it can be seen that the orientation crystallinity degree increases as the draw ratio increases.

  According to the present invention, as described above, the stretched molded article is obtained by performing a biaxial stretching operation in which a negative gradient is provided to the stretching speed that increases the initial stretching speed and decreases the final stretching speed of the aliphatic polyester. In the range where the strength characteristic of the material satisfies the formula (1), the anisotropy of the mechanical strength is eliminated or reduced, and the improvement of the anisotropy is a region where the orientation crystallinity (Do) is 0.15 or more. It should be noted that this is achieved in

(Aliphatic polyester resin)
In the present invention, as the aliphatic polyester resin, any biodegradable aliphatic polyester resin mainly composed of hydroxyalkanoate units is used. The aliphatic polyester resin should have at least a molecular weight capable of forming a film, and generally its number average molecular weight should be in the range of 10,000 to 300,000, particularly 20,000 to 200,000. Examples of suitable aliphatic polyester resins are polyhydroxyalkanoates or copolymers thereof.

式中、Ｒは水素原子、または直鎖或いは分岐鎖のアルキル基であり、ｎはゼロを含む正の整数である、で表される反復単位、例えば、乳酸［Ｒ＝ＣＨ_３、ｎ＝０、ＬＬＡ］、３−ヒドロキシブチレート［Ｒ＝ＣＨ_３、ｎ＝１、３ＨＢ］、３−ヒドロキシバリレート［Ｒ＝ＣＨ_２ＣＨ_３、ｎ＝１、３ＨＶ］、３−ヒドロキシカプロエート［Ｒ＝（ＣＨ_２）_２
ＣＨ_３、ｎ＝１、３ＨＣ］、３−ヒドロキシヘプタノエート［Ｒ＝（ＣＨ_２）_３ＣＨ_３、ｎ＝１、３ＨＨ］、３−ヒドロキシオクタノエート［Ｒ＝（ＣＨ_２）_４ＣＨ_３ｎ＝１、３ＨＯ］、３−ヒドロキシノナノエート［Ｒ＝（ＣＨ_２）_５ＣＨ_３、ｎ＝１、３ＨＮ］、３−ヒドロキシデカノエート［Ｒ＝（ＣＨ_２）_６ＣＨ_３、ｎ＝１、３ＨＤ］、γ−ブチロラクトン［Ｒ＝Ｈ、ｎ＝２、ＢＬ］、δ−バレロラクトン［Ｒ＝Ｈ、ｎ＝３、ＶＬ］、ε−カプロラクトン［Ｒ＝Ｈ、ｎ＝４、ＣＬ］
等の１種或いは２種以上からなる重合体が挙げられる。 The polyhydroxyalkanoate has the following formula:

In the formula, R is a hydrogen atom or a linear or branched alkyl group, and n is a positive integer including zero, for example, lactic acid [R = CH ₃ , n = 0 LLA], 3-hydroxybutyrate [R = CH ₃ , n = 1, 3HB], 3-hydroxyvalerate [R = CH ₂ CH ₃ , n = 1, 3HV], 3-hydroxycaproate [R = (CH ₂ ) ₂
CH ₃ , n = 1, 3HC], 3-hydroxyheptanoate [R = (CH ₂ ) ₃ CH ₃ , n = 1, 3HH], 3-hydroxyoctanoate [R = (CH ₂ ) ₄ CH ₃ n = 1, 3HO], 3-hydroxynonanoate [R = (CH ₂ ) ₅ CH ₃ , n = 1, 3HN], 3-hydroxydecanoate [R = (CH ₂ ) ₆ CH ₃ , n = 1 3HD], γ-butyrolactone [R = H, n = 2, BL], δ-valerolactone [R = H, n = 3, VL], ε-caprolactone [R = H, n = 4, CL]
The polymer which consists of 1 type, or 2 or more types, etc. is mentioned.

  This polyhydroxyalkanoate is composed of polylactic acid (polylactic acid (poly (L-lactic acid) whose structural unit is composed only of L-lactic acid), poly (D-lactic acid) composed of only D-lactic acid, and L-lactic acid unit and D -Poly (DL-lactic acid) present in an arbitrary proportion of lactic acid species.) Also, it may be a homopolymer such as poly-ε-caprolactone or a copolymer with other hydroxyalkaliates. Further, it may be a copolymer obtained by copolymerizing 3-hydroxybutyrate and another 3-hydroxyalkanoate, particularly 3-hydroxyvalerate.

  The aliphatic polyester used in the present invention preferably has a glass transition point (Tg) of -60 ° C or higher, particularly 30 ° C or higher. Among these aliphatic polyesters, polylactic acid is an example of an aliphatic polyester that is industrially mass-produced and easily available and is also environmentally friendly. Polylactic acid (PLLA) is a resin made from cereal starch such as corn, and is a lactic acid fermentation product of starch and a polymer containing L-lactic acid as a monomer. In general, the dimer is produced by a ring-opening polymerization method of lactide and a direct polycondensation method. This polymer is decomposed by water and carbon dioxide by microorganisms that exist in nature, and has attracted attention as a completely recycle system type resin. In addition, the glass transition point (Tg) has an advantage of about 58 ° C., which is close to the Tg of PET.

  The stretched molded product of the present invention can use the above aliphatic polyester, particularly polylactic acid alone, or can be used as a blend with other aliphatic polyesters or other resins or as a laminate with other resins. You can also.

  Further, other resins that can be used in the form of blends or laminates with the above aliphatic polyesters include barrier resins, such as hydroxyl group-containing thermoplastic resins that exhibit barrier properties against oxygen, nylon resins, and barrier polyester resins. , A high nitrile resin, and a cyclic olefin copolymer showing a barrier property against water vapor. Among these, a hydroxyl group-containing resin is preferable in terms of biodegradability, and any resin can be used as long as thermoforming is possible. This resin has a repeating unit having a hydroxyl group and a unit imparting thermoformability to the resin in its molecular chain. The hydroxyl group-containing repeating unit may be a vinyl alcohol unit or a hydroxyalkyl (meth) acrylate unit, but a vinyl alcohol unit is preferred in terms of biodegradability. Examples of other units contained in the hydroxyl group-containing resin include olefin units such as ethylene and propylene, vinyl ester units such as vinyl acetate, and alkyl (meth) acrylate units. Also, these hydroxyl group-containing resins should have at least a molecular weight sufficient to form a film.

  A preferred hydroxyl group-containing resin comprises a copolymer containing 10 to 40 mol% ethylene units, 40 to 88 mol% vinyl alcohol units, and 50 mol% or less ester-containing vinyl units. By using such a hydroxyl group-containing polymer as a blend or a laminate, it is possible to improve the gas barrier properties of the stretch-molded product and to achieve the advantage that the biodegradability is not substantially inhibited.

  The stretched molded product of the present invention has various colorants, fillers, inorganic or organic reinforcing agents, lubricants, plasticizers, leveling agents, surfactants, thickeners, thickeners depending on the application. Stabilizers, antioxidants, ultraviolet absorbers, rust inhibitors and the like can be blended according to known formulations.

(Stretched compact and its production method)
The stretch-molded product of the present invention is obtained by subjecting a preform of a resin mainly composed of aliphatic polyester to biaxial stretching with a negative gradient in the stretch rate of increasing the initial stretch rate and decreasing the final stretch rate. Manufactured by performing.

  The preform (preform) can be produced by a known extrusion molding method, injection molding method or compression molding method. For example, by extruding the molten resin through a T-die, a thin sheet of stretched film and a sheet for pressure-air molding or plug assist molding on a film or cup are formed. Moreover, the pipe-shaped preform for container shaping | molding can also be shape | molded by extruding molten resin through a ring die. Furthermore, a preform for a three-dimensional container such as a bottle is formed by injecting the molten resin into a mold composed of a cavity mold and a core mold with a screw or a plunger. Further, a three-dimensional preform such as a bottle can be obtained by compressing a molten resin parison with a cavity mold and a core mold.

  In order to produce a preform formed of a laminate of an aliphatic polyester and another resin, such as a hydroxyl group-containing resin, a known lamination technique is used. For example, in the case of an extrusion molding method, it corresponds to the type of resin. A multilayer preform is produced by coextrusion using a multilayer die using an extruder. In injection molding, a multilayer preform can be formed by a co-injection method or a sequential co-injection method known per se. Furthermore, even by the compression molding method, a multilayer preform can be produced by forming a multilayer molten resin parison by coextrusion or the like.

  The preform is stretch-molded under the conditions that the stretching speed of the aliphatic polyester is the same as that described above, and the orientation crystallinity (Do) of the resulting molded body is 0.15 or more.

  The stretching temperature varies depending on the type of aliphatic polyester, but generally speaking, a temperature of Tg to Tg + 60 ° C. is appropriate based on the glass transition point (Tg) of the aliphatic polyester. In this case, a temperature of Tg + 10 ° C. to Tg + 20 ° C. is appropriate.

In the present invention, biaxial stretching is performed in which a negative gradient is provided to the stretching speed with the initial stretching speed increased and the final stretching speed decreased, but the first stage stretching speed (V ₁ ) and the final stage stretching are performed. the ratio of the velocity _{(V 2) (V 1 /} V 2) is generally in the range of 3 to 70 is preferable in order to eliminate or reduce the anisotropy of the strength. That is, when the ratio of V ₁ / V ₂ is less than the above range, it tends to be difficult to improve the strength characteristics so as to satisfy the formula (1), while when this ratio exceeds the above range. Since productivity of stretch molding is deteriorated, it is not preferable.

  The stretching speed in the first stage is not particularly limited, but it is generally desirable to be in the range of 1 m / sec to 50 m / sec. The change in the stretching speed can be changed stepwise over two or more stages, or can be changed continuously. Of course, in any of these cases, it is necessary to provide a gradient in the stretching speed so that the stretching speed monotonously decreases from the initial stage of stretching to the final stage. The stretching speed can be switched by changing the moving speed of the stretching rod or the gripping chuck in the mechanical stretching, and by changing the blow pressure in the expansion stretching.

  The draw ratio is such that the orientation crystallinity (Do) defined by the formula (2) is 0.15 or more, and generally speaking, the draw ratio in the machine direction (container axis direction) is The stretching ratio is 1.4 to 4 times, the transverse direction (container circumferential direction) stretch ratio is 1.4 to 4 times, and the area stretch ratio is preferably 2 to 16 times.

  In the stretch molding of the present invention, the reason why the strength anisotropy is eliminated or reduced by providing a negative gradient in the stretching speed has not yet been elucidated. However, under such stretching conditions, the possibility of relaxation of strain due to stretching and a kind of heat setting cannot be denied.

  The stretched molded article of aliphatic polyester according to the present invention has anisotropy in mechanical strength and is excellent in various properties as a container, but is slightly inferior in gas barrier properties as compared with aromatic polyester. Tend. In order to improve this, it is preferable to form a hard carbon film on at least one surface of the stretched molded body by chemical vapor deposition (CVD).

The hard carbon film is generally called a DLC (diamond like carbon) film, i-carbon film or hydrogenated amorphous carbon film (aC: H), and is composed of an amorphous carbon film mainly composed of SP ³ bonds. ing. This carbon film is excellent in the sorption suppressing effect and gas barrier properties of low-molecular organic compounds such as flavor components. The thickness of the carbon film is preferably in the range of 0.05 to 5 μm from the viewpoints of improvement of these characteristics, adhesion to plastic, durability, transparency, and the like.

  The hard carbon film can be formed by a chemical vapor deposition method (CVD) known per se, particularly plasma CVD. Plasma CVD is a method in which a thin film is grown by using gas plasma. Basically, a gas containing a source gas is discharged under a reduced pressure with electric energy by a high electric field, decomposed, and a substance to be generated is generated. It consists of a process of depositing on a substrate through a chemical reaction in the gas phase or on the substrate. The plasma state is realized by glow discharge. Depending on the glow discharge method, a method using a direct current glow discharge, a method using a high frequency glow discharge, a method using a microwave discharge, etc. are known. Yes.

  Plasma CVD uses (1) direct decomposition of gas molecules by fast electrons, so it can easily dissociate raw material gas with large generation energy. (2) Thermal non-equilibrium state where electron temperature and gas molecule temperature are different. The low-temperature process is possible, and (3) a relatively uniform amorphous film can be formed even when the substrate temperature is low. It is.

  As a raw material gas for film formation, gaseous or liquid aliphatic hydrocarbons, aromatic hydrocarbons, oxygen-containing hydrocarbons, nitrogen-containing hydrocarbons and the like are used at room temperature. Among these, benzene, toluene, o-xylene, m-xylene, p-xylene, cyclohexane and the like having 6 or more carbon atoms are preferable. These raw materials can be used singly or as a mixed gas of two or more, and these gases may be diluted with a rare gas such as argon or helium.

For the formation of the hard carbon film, the reaction container is filled with an aliphatic polyester stretched molded body, and the reaction container is evacuated. In general, the degree of vacuum at this time is preferably in the range of 10 ⁻² to 10 ⁻⁵ torr. Next, the raw material gas is supplied into the reaction vessel, glow discharge is started, and film formation is performed. The pressure in the reaction vessel is preferably in the range of 0.5 to 0.001 torr. In order to further improve the adhesion between the carbon film and the molded body, the surface of the molded body can be activated by performing plasma treatment with an inorganic gas such as argon or oxygen before forming the carbon film.

(Use)
The stretched molded product of the present invention can be used for various plastic packaging containers such as bottles, cups, tubes, plastic cans, pouches, caps, etc., and as packaging materials for films, trays, etc., and containers for distribution such as containers, tanks, bags, etc. Further, it is useful as a structure such as a pipe or a case.

  Next, the present invention will be described with specific examples. In addition, this invention is not limited to a following example.

(Molding)
Bottle molding: Polylactic acid having a weight average molecular weight of 180,000 was used. A preform having a diameter of 28 mmφ was injection molded under conditions of 190 to 200 ° C. using an injection molding machine. Mold temperature 15 ° C. Next, the preform was reheated to 65 to 75 ° C. with an infrared heater, and then a round 500 ml mold blow bottle was prepared using a mold blow molding machine. In this case, constant pressure blow molding was performed with the blow pressure set to a compressed air pressure of 30 kg / cm ² . In addition, after the compressed air blowing port and the exhaust port are provided side by side and the initial compressed air pressure is set to 30 kg / cm ² , the exhaust valve is opened for a while, and the blow pressure is gradually reduced within the blow time to obtain the final blow Mold blow was performed with the pressure reduced to 0.5 kg / cm ² .

Cup molding: The polylactic acid was used. Using an extruder, C1-C4 of the screw part was 190-200 ° C., the T-die temperature was 190 ° C., and a sheet of 400 mm width and 2 mm thickness was prepared. This sheet was reheated to 70 ° C. using a thermoform molding machine, and then stretched in the longitudinal direction with a conical plug assist, and at the same time, a cylindrical cup was molded with compressed air. (Aperture 80mmφ, bottom diameter 50mmφ, height 90mm). Mold temperature 15 ° C. In this case, molding was performed with the pressure of the compressed air blown at a constant pressure of 10 kg / cm ² and molding with the pressure of the blown compressed air varied from the initial air pressure of 10 kg / cm ² to 0.5 kg / cm ² .

  Stretched sheet molding: The polylactic acid was used. Using an injection molding machine, a 2 mm thick 11 mm × 11 mm size flat plate was injection molded at 190 to 200 ° C. Mold temperature 15 ° C. Next, the injection-molded flat plate was reheated to 70 ° C. using a biaxial stretching apparatus, and then simultaneously biaxial at 2 × 2, 2.5 × 2.5, and 3 × 3 at a stretching speed of 10 m / min. Stretched. Further, simultaneous biaxial stretching was performed with the stretching ratio kept constant at 3 × 3 times and the stretching speed was changed to 50 mm / min, 500 mm / min, and 1000 mm / min. Similarly, the stretching ratio is 3 × 3 times, the initial stretching speed is 1000 mm / min, and biaxial stretching is performed by gradually reducing the stretching speed to 500 mm / min and 50 mm / min within the biaxial stretching time. went.

(Evaluation)
Stretching stress of biaxially stretched sheet: The stretching stress during biaxial stretching was measured using a biaxial stretching device manufactured by Toyo Seiki Co., Ltd. In this case, the stretching axes were biaxial, but the stretching stress of each stretching axis showed the same pattern. For this reason, the uniaxial stretching stress was shown.
Mechanical strength: A biaxially stretched sheet was used. ASTMD-1822 dumbbells were cut out in the direction with the axes of the drawing axis (X, Y) as the axis and the diagonal direction (45 ° direction) formed by the two biaxial directions as the axes, and a tensile test made by ORIENTEC A tensile stress-strain curve was obtained with a machine.
Compressive strength: A mold blow bottle and a thermoform molding cup were used. A compression strain test with a strain amount of 10% was performed using a 10 mmφ jig on the bottle and the body (lateral direction) of the cup. The bottle and the cup that produced a crack in the body direction during strain deformation were set as x, and the bottle and the cup that did not generate a crack during deformation were marked as ◯.

¹³ C wide-width NMR measurement: using a JEOL NMR device, using a biaxially stretched sheet, a mold blow bottle, and a section cut out from a thermoform cup to a width of 4 mm, and aligning the cutting direction and overlaying After that, it was filled into a Daiflon holder. Thereafter, ¹³ C wide NMR measurement was performed. Also, the target nucleus was limited to the carbonyl carbon region. The obtained NMR spectrum shows the amorphous pattern shown in FIG. 1 if only the non-oriented component is present. If an orientation component exists, in addition to the amorphous pattern shown in FIG. 2R> 2, an angle-dependent spectral pattern formed by the orientation axis of the orientation component and the direction of the static magnetic field of NMR as shown in FIGS. (Example, X FIG. 3 → vertical, FIG. 4 → parallel). Therefore, the composition fraction of the oriented crystal component can be obtained by subtracting the powder pattern shown in FIG. 2 from the actually measured ¹³ C wide NMR measurement spectrum. First, a thin amorphous sample obtained by rapidly cooling a molten sample was prepared, cut into small pieces, randomly filled into a sample tube made by Daiflon, and subjected to ¹³ C wide-width NMR measurement (FIG. 1). Next, the sections cut out from the biaxially stretched sheet, the mold blow bottle, and the thermoform cup were overlapped with the cut-out directions aligned, and ¹³ C wide NMR measurement was performed. Each measured spectrum was read with an image scanner, and then the X and Y coordinates of the spectrum were obtained. After that, with a spreadsheet software (Microsoft, Excel (registered trademark)), the powder pattern of the non-oriented component was obtained from the ¹³ C wide NMR spectrum of the biaxially stretched sheet, the mold blow bottle, and the section of the thermoform cup. deducted. The spectral peak intensity before the calculation was S. The amorphous component subtracted by calculation was defined as Sa. In this case, S-Sa = Sc is the oriented crystal component. Therefore, here, Do = (S−Sa) / S indicates the composition of the oriented crystal component. The ¹³ C broad NMR measurement shown here is a general analytical technique.

[Example 1]
A 2 mm-thick flat plate was reheated to 70 ° C. and then subjected to simultaneous biaxial stretching at a stretching ratio of 3 × 3 using a biaxial stretching apparatus. The initial stretching speed was 1000 mm / min, and the stretching speed was gradually reduced to 500 mm / min and 50 mm / min within the simultaneous biaxial stretching time. For the above-mentioned simultaneous biaxially stretched sample, the mechanical strength (yield point strength) in the stretch axis direction and the diagonal direction (45 ° direction), the stretch stress pattern during biaxial stretching of the sample, and ¹³ C wide-width NMR measurement Table 1 shows the orientation crystallinity obtained from the above.

[Comparative Example 1]
After reheating the 2 mm thick flat plate to 70 ° C., simultaneous biaxial stretching with a stretching ratio of 3 × 3 was performed using a biaxial stretching apparatus. Stretching was performed at a constant speed of 1000 mm / min, 500 mm / min, and 50 mm / min. From the above-mentioned simultaneous biaxially stretched sample, the mechanical strength (yield point strength) in the stretched axis direction and the diagonal direction (45 ° direction), the stretch stress pattern during biaxial stretching of the sample, and ¹³ C wide-width NMR The obtained orientation crystallinity is shown in Table 1.

[Comparative Example 2]
A 2 mm thick flat plate was reheated to 70 ° C. and then subjected to simultaneous biaxial stretching using a biaxial stretching apparatus. The stretching speed was set to a constant speed of 10 m / min, and the stretching ratio was changed to 2 × 2, 2.5 × 2.5, and 3 × 3 times. About the simultaneous biaxially stretched sample, the mechanical strength (yield point strength) in the stretch axis direction and the diagonal direction (45 ° direction), the stretch stress pattern during biaxial stretching of the sample, and ¹³ wide CNMR Table 2 shows the orientation crystallinity.

[Example 2]
The polylactic acid was used. Using an extruder, a sheet having a width of 400 mm and a thickness of 2 mm was prepared in which C1 to C4 of the screw portion were 190 to 200 ° C. and the T die temperature was 190 ° C. The sheet with thermofoam molding machine, after reheated to 70 ° C., the cylindrical cup and 1Kg / cm ² low-pressure air when stretched in the longitudinal direction from the initial compression pressure 15 Kg / cm ² at the same time at the end in conical plug-assisted Was molded. (Aperture 80mmφ, bottom diameter 50mmφ, height 90mm) Mold temperature 15 ° C. A 10 mmφ flat plate jig was used for the cup body (lateral direction), and the cup body was compressed and deformed with an amount of 10% strain. A cup that did not cause cracks in the barrel during compression strain deformation was marked as ◯, and a cup that cracked in the barrel during deformation was marked as x. The results are shown in Table 3.

[Comparative Example 3]
The polylactic acid was used. Using an extruder, a sheet having a width of 400 mm and a thickness of 2 mm was prepared with a screw part temperature, C1 to C4 of 190 to 200 ° C., and a T die temperature of 190 ° C. This sheet was heated to 70 ° C. using a thermoform molding machine, and then stretched in the longitudinal direction with a conical plug assist, and simultaneously molded into a cylindrical cup with compressed air. (Aperture 80mmφ, bottom diameter 50mmφ, height 90mm) Mold temperature 15 ° C. In this case, the pressure of the blown compressed air was set to 15 kg / cm ² . A 10 mmφ flat plate jig was used for the cup body (lateral direction), and was subjected to compressive strain deformation with a strain amount of 10%. After strain deformation, the cup that did not crack in the barrel was marked with ◯, and the cup x that cracked in the barrel during deformation. The results are shown in Table 3.

[Example 3]
The polylactic acid was used. A 28 mmφ preform was injection molded under 190 to 200 ° C. using an injection molding machine. Mold temperature 15 ° C. The preform was reheated to 70 to 75 ° C. using an infrared heater, and then a round 500 ml blow bottle was prepared with a mold blow molding machine. The blow pressure at the time of blow was set up with a compressed air blowing port and an exhaust port, and after initially setting the compressed air pressure to 30 kg / cm ² , the exhaust valve was opened for a while and the blow pressure was reduced stepwise within the blow time. . Finally, the pressure was reduced to 0.5 kg / cm ² and the mold was blown. The body part (lateral direction) of the molding die blow bottle was subjected to compression strain deformation to a strain amount of 10% using a 10 mmφ flat plate jig. After compression strain deformation, a bottle in which the body portion was not cracked was marked as ◯, and a bottle in which the body portion was cracked during strain deformation was marked as ×. The results are shown in Table 3.

[Comparative Example 4]
The polylactic acid was used. A preform having a nozzle diameter of 28 mmφ was injection-molded using an injection molding machine at 190 to 200 ° C. Mold temperature 15 ° C. The preform was reheated to 70 to 75 ° C. using an infrared heater, and then a 500 ml round blow bottle was prepared with a mold blow molding machine. The compressed air at the time of blowing was constant pressure blow molding to 30 Kg / cm ^2. About the said shaping | molding die blow bottle, the trunk | drum (lateral direction) was made into the compression strain deformation | transformation of the amount of strain 10% using the 10 mm diameter flat plate jig. After compression strain deformation, a bottle in which the body portion was not cracked was marked as ◯, and a bottle in which the body portion was cracked during strain deformation was marked as ×. The results are shown in Table 3.

  Next, preparation and measurement of samples were shown in Examples and Comparative Examples regarding aliphatic polyester stretch moldability in which a hard carbon film was formed.

(Bottle molding)
A preform having a diameter of 28 mmφ was injection-molded from polylactic acid using an injection molding machine at 190 ° C to 200 ° C. Mold temperature 15 ° C. Next, the preform was reheated to 65 to 75 ° C. with an infrared heater, and a mold blow bottle having a 500 ml average wall thickness of 300 μm was prepared using a mold blow molding machine. In this case, by features a compressed air blowing port and the exhaust port, after the initial compression pressure and 30 Kg / cm ^2, the pressure was reduced in stages blowdown time. Mold blow molding was performed with a final blow pressure of 0.5 kg / cm ² . Moreover, the die blow molding which made the blow pressure the constant pressure of 30 kg / cm < ² > was performed.

(Sheet molding)
Using an extruder for polylactic acid, a 200 mm wide and 2 mm thick sheet was formed in which the C1 to C4 temperature of the screw part was 190 ° C to 200 ° C and the T die temperature was 190 ° C. Then, it reheated to 65 to 75 degreeC using the heating oven, and 3 * 3 times biaxial stretching was performed using the modified tenter type biaxial stretching machine (average thickness: 200 micrometers). In this case, the initial stretching speed was set to 1 m / min, and the stretching speed was gradually reduced to 0.05 m / min until reaching a predetermined stretching ratio. Moreover, the constant speed extending | stretching shaping | molding which made the extending | stretching speed 1 m / min was performed.

(Carbon film formation)
(Bottle)
In a CVD vapor deposition apparatus, using a bottle-shaped electrode and an electrode installed inside the bottle, the pressure inside the bottle is reduced to a vacuum, and then a hexane / argon mixed gas is used as a raw material gas. A 56 MHz PE-CVD carbon film was deposited. Deposition temperature 25 ° C.
(Stretched sheet) PE-CVD carbon film deposition with a film forming pressure of 0.1 torr and a high frequency power of 13.56 MHz was performed using flat plate electrodes set up and down in the vacuum chamber and using a mixed gas of hexane and argon as a raw material gas. Deposition temperature 25 ° C.

(Oxygen gas barrier properties)
(Bottle)
The prototype bottle was placed in a vacuum chamber, vacuum decompressed, and then high purity nitrogen gas was introduced to replace the gas phase in the bottle with nitrogen gas. Then, it sealed with the rubber stopper. It preserve | saved on 30 degreeC-RH80% conditions of oxygen concentration 20.9%. Three weeks later, the air in the bottle was collected using a gas tight syringe, subjected to GC analysis, and converted to BO ₂ .
(Stretched sheet)
Using a gas transmission tester manufactured by Mocon, the oxygen permeability was measured under the condition of 40 ° C. and converted into an oxygen permeability coefficient.

(Mechanical strength)
(Bottle)
A compression strain test with a strain amount of 10% was performed using a 10 mmφ jig on the bottle body (lateral direction) after vapor deposition of the mold blow bottle and the carbon thin film. A bottle in which cracks were generated in the body direction during strain deformation was marked with ×, and a bottle with no cracks during deformation was marked with ○.
(Stretched sheet)
ASTM-1822 dumbbells are cut out in the direction using the biaxially stretched sheet as the axis with the direction of the stretched axis (X, Y) as the axis and the direction as the diagonal direction (45 °) between the stretched biaxial as the axes. The tensile stress-strain curve was obtained with a tensile tester manufactured by ORIENTEC.

[Example 4]
A preform having a diameter of 28 mmφ was injection-molded from polylactic acid using an injection molding machine at 190 ° C to 200 ° C. Mold temperature 15 ° C. Next, the preform was reheated to 65 ° C. to 75 ° C. with an infrared heater, and a mold blow bottle having a 500 ml average wall thickness of 300 μm was prepared using a mold blow molding machine. In this case, the compressed air blowing port and the exhaust port were provided side by side, the initial compressed air pressure was set to 30 kg / cm ^2, and then the pressure was reduced stepwise within the blowing time. Mold blow molding was performed with a final blow pressure of 0.5 kg / cm ² . Next, in a CVD deposition apparatus, a bottle-shaped electrode and an electrode installed inside the bottle are used, the pressure inside the bottle is reduced to a vacuum, and a mixed gas of hexane / argon is used as a raw material gas. PE-CVD carbon film deposition with a power of 13.56 MHz was performed. Deposition temperature 25 ° C. BO ₂ obtained by storing the bottle after deposition of the carbon film at 40 ° C.-RH 80% with an oxygen concentration of 20.9% was obtained. Further, a 10 mmφ jig was used for the bottle body (lateral direction), and a compressive strain test with a strain amount of 10% was performed. A bottle in which cracks were generated in the body direction during strain deformation was marked with ×, and a bottle with no cracks during deformation was marked with ○. The results obtained are shown in Table 4.

[Comparative Example 5]
A preform having a diameter of 28 mmφ was injection-molded from polylactic acid using an injection molding machine at 190 ° C to 200 ° C. Mold temperature 15 ° C. Next, the preform was reheated to 65 ° C. to 75 ° C. with an infrared heater, and a mold blow bottle having a 500 ml average wall thickness of 300 μm was prepared using a mold blow molding machine. In this case, the compressed air blowing port and the exhaust port were provided side by side, the initial compressed air pressure was set to 30 kg / cm ^2, and then the pressure was reduced stepwise within the blowing time. Mold blow molding was performed with a final blow pressure of 0.5 kg / cm ² . After the bottle was replaced with nitrogen, BO ₂ was obtained by storing the bottle at 30 ° C.-RH 80% with an oxygen concentration of 20.9%. Further, a 10 mmφ jig was used for the bottle body (lateral direction), and a compressive strain test with a strain amount of 10% was performed. The bottle in which cracks were generated in the body direction during strain deformation was marked with ×, and the bottle with no cracks during deformation was marked with ○. The results obtained are shown in Table 4.

[Comparative Example 6]
A preform having a diameter of 28 mmφ was injection-molded from polylactic acid using an injection molding machine at 190 ° C to 200 ° C. Mold temperature 15 ° C. Next, the preform was reheated to 65 ° C. to 75 ° C. with an infrared heater, and a mold blow bottle having a 500 ml average wall thickness of 300 μm was prepared using a mold blow molding machine. In this case, mold blow molding was performed with the compressed air pressure set to a constant pressure of 30 kg / cm ² . Next, in a CVD deposition apparatus, a bottle-shaped electrode and an electrode installed inside the bottle are used, the pressure inside the bottle is reduced to a vacuum, and a mixed gas of hexane / argon is used as a raw material gas. PE-CVD carbon film deposition with a power of 13.56 MHz was performed. Deposition temperature 25 ° C. The bottle after deposition of the carbon film was stored in 30 ° C.-RH 80% with an oxygen concentration of 20.9% to obtain BO ₂ of the bottle. Further, a 10 mmφ jig was used for the bottle body (lateral direction), and a compressive strain test with a strain amount of 10% was performed. A bottle in which cracks were generated in the body direction during strain deformation was marked with ×, and a bottle with no cracks during deformation was marked with ○. The results obtained are shown in Table 4.

[Example 5]
Using an extruder for polylactic acid, a 200 mm wide and 2 mm thick sheet was formed in which the C1 to C4 temperature of the screw part was 190 ° C to 200 ° C and the T die temperature was 190 ° C. Then, it reheated to 65 to 75 degreeC using the heating oven, and 3 * 3 times biaxial stretching was performed using the modified tenter type biaxial stretching machine (average thickness: 200 micrometers). In this case, the initial stretching speed was set to 10 m / min, and the stretching speed was gradually reduced to 0.05 m / min until the predetermined stretching ratio was reached. Next, PE-CVD carbon film deposition with a film forming pressure of 0.1 torr and a high frequency power of 13.56 MHz was performed using flat plate electrodes set in the upper and lower portions of the vacuum chamber and using a mixed gas of hexane and argon as a source gas. Deposition temperature 25 ° C. Furthermore, using a gas transmission tester manufactured by Mocon, the oxygen permeability was measured under the condition of 40 ° C. and converted into an oxygen permeability coefficient. Furthermore, ASTM-1822 type dumbbells were cut out in the direction with the extending axis direction (X, Y) as the axis and the diagonal direction (45 °) formed by the extending two axes as the axes, respectively, and a tensile test made by ORIENTEC A tensile stress-strain curve was obtained with a machine. The obtained results are shown in Table 5.

[Comparative Example 7]
Using an extruder for polylactic acid, a 200 mm wide and 2 mm thick sheet was formed in which the C1 to C4 temperature of the screw part was 190 ° C to 200 ° C and the T die temperature was 190 ° C. Then, it reheated to 65 to 75 degreeC using the heating oven, and 3 * 3 times biaxial stretching was performed using the modified tenter type biaxial stretching machine (average thickness: 200 micrometers). In this case, the initial stretching speed was 10 m / min, and the stretching speed was gradually reduced to 0.05 m / min until a predetermined stretching ratio was reached. Using the stretched sheet, an oxygen permeability coefficient was measured under a 40 ° C. condition using a Mocon gas permeability tester and converted to an oxygen permeability coefficient. Furthermore, ASTM-1822 type dumbbells were cut out in the direction with the extending axis direction (X, Y) as the axis and the diagonal direction (45 °) formed by the extending two axes as the axes, respectively, and a tensile test made by ORIENTEC A tensile stress-strain curve was obtained with a machine. The obtained results are shown in Table 5.

[Comparative Example 8]
Using a polylactic acid injection molding machine, a sheet having a width of 200 mm and a thickness of 2 mm was formed in which the C1 to C4 temperature of the screw part was 190 ° C to 200 ° C and the T die temperature was 190 ° C. Then, it reheated to 65 to 75 degreeC using the heating oven, and 3 * 3 times biaxial stretching was performed using the modified tenter type biaxial stretching machine (average thickness: 200 micrometers).
In this case, the stretching speed was a constant stretching speed of 10 m / min. Next, in a CVD deposition apparatus, a bottle-shaped electrode and an electrode installed inside the bottle are used, the pressure inside the bottle is reduced to a vacuum, and a mixed gas of hexane / argon is used as a raw material gas. PE-CVD carbon film deposition with a power of 13.56 MHz was performed. Deposition temperature 25 ° C. Using the stretched sheet, an oxygen transmission coefficient was measured under a 40 ° C. condition using a gas transmission tester manufactured by Mocon, and converted to an elementary transmission coefficient. Furthermore, ASTM-1822 type dumbbells were cut out in the direction with the extending axis direction (X, Y) as the axis and the diagonal direction (45 °) formed by the extending two axes as the axes, respectively, and a tensile test made by ORIENTEC A tensile stress-strain curve was obtained with a machine. The obtained results are shown in Table 5.

It is a graph which shows the relationship between the draw ratio (axial direction draw ratio, area draw ratio) and orientation crystallinity degree (Do) which were obtained about the various stretch-molded articles about an aliphatic polyester stretch-molded body. The ¹³ C broad NMR spectrum pattern of the non-oriented aliphatic polyester was shown. The ¹³ C wide NMR spectrum pattern of the aliphatic polyester was shown when the orientation axis and the direction of the static magnetic field of NMR were perpendicular. The ¹³ C wide NMR spectrum pattern of the aliphatic polyester was shown when the orientation axis and the direction of the static magnetic field of NMR were parallel.

Claims (1)

  A resin sheet mainly composed of aliphatic polyester is formed by pressure forming or plug assist molding under a certain stretching temperature, with the stretching speed being variably controlled so that the initial stretching speed is large and the final stretching speed is small. A cup having strength enough to withstand 10% compression strain.

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