WO2022048584A1 - Material, preparation method therefor, and application thereof - Google Patents

Abstract

Disclosed in the present invention is a material containing at least two structural layers, and the degrees of crystallinity of adjacent structural layers are different; the structural layers are formed of a degradable resin.

Description

A kind of material and its preparation method and application technical field

The present invention relates to polymer materials, in particular to a degradable polymer material based on the regulation of crystalline region distribution.

Background technique

Degradable polymer material refers to a polymer material that can be degraded in the sense of thermodynamics and kinetics under certain time and conditions. It is an environmentally friendly polymer material and can be used in all aspects of production and life, such as, It can be produced by blow molding to produce film products, such as shopping bags, packaging bags, garbage bags, gloves and agricultural films, etc.; can be produced by injection molding to produce container products, such as bottles, etc.; can also be produced by extrusion molding to produce sheets and Pipes, etc., such as plates, bowls, basins, lunch boxes, folders, ropes, straws, hard pipes, etc.; also can be prepared by injection molding to prepare a variety of injection molding products, such as chopsticks, cutlery, pens, stationery, toothbrushes, combs, Clothes hangers and structural parts and casings of electronic products, etc.; can also be formed by spinning (for example, melt spinning or solution spinning, etc.) to prepare fiber products, such as long fibers, short fibers, non-woven fabrics, etc.

Because the existing degradable polymer materials are usually polymerized from functional group-containing monomers to form several thousand, tens of thousands, millions or even tens of millions of hydrolyzable functional groups (for example, ester groups) , amide group, acid anhydride or urethane group, etc.), so its many properties (for example, mechanical properties, processing properties, degradation properties, thermal stability, gas barrier properties, aging resistance, etc.) mainly depend on its Internal structural properties (eg, molecular chain structure, molecular chain morphology, molecular chain configuration, conformation and flexibility, molecular weight size, molecular weight distribution, crystallinity, types of hydrolyzable bonds, etc.).

At present, the performance regulation of degradable polymer materials is mostly realized by using related processing aids. For example, with regard to degradation performance, in general, once a degradable polymer material is selected, the regulation of its degradation performance is usually to add some additives (such as water absorbent, Hydrolysis promoters, anti-hydrolysis agents, etc.). This will not only increase the processing cost of the material, but also the use of the above-mentioned additives will also control the degradation performance of the final material due to factors such as uneven dispersion in the matrix, poor compatibility with the matrix, and partial analysis. Unfavorable effects, and even undesired unstable degradation such as slow and fast, uneven degradation, etc. may occur.

Therefore, there is an urgent need in the art for a new idea that can accurately control the properties (for example, mechanical properties, degradation properties, heat resistance, etc.) of degradable polymer materials.

SUMMARY OF THE INVENTION

The present invention aims to provide a degradable polymer material based on the regulation of crystal region distribution, and a preparation method and application thereof.

In a first aspect of the present invention, a material is provided, the material contains at least two structural layers, and adjacent structural layers have different degrees of crystallinity; the structural layers are formed of a degradable resin.

In another embodiment, the crystallinity of adjacent structural layers differs by 0.1-72%.

In another embodiment, each structural layer is formed from the same or different degradable resins.

In another embodiment, the degradable resin has a hydrolyzable functional group, and the hydrolyzable functional group is selected from one or more of the following: ester group, amide group, hydroxyl group, carboxyl group, acid anhydride and urethane group; for example, the degradable resin is selected from one or more of the following copolymers, mixtures, derivatives or combinations: aliphatic polyesters, polyhydroxyester ethers, polyhydroxyalkanoates, Polyanhydrides, polyamino acids, polyethylene oxides, polyphosphazenes, polyetheresters, polyesteramides, polyamides, sulfonated polyesters, thermoplastic polyester elastomers, thermoplastic polyamide elastomers, and thermoplastic polyurethane elastomers.

In another embodiment, the aliphatic polyester is selected from one or more of the following: glycolic acid homopolymer, glycolic acid copolymer, polylactic acid and its copolymer, poly-ε-caprolactone (referred to as PCL), polyethylene succinate (referred to as PES), polybutylene succinate (referred to as PBS), polyadipate-terephthalate-butylene glycol (referred to as PBAT), Polysuccinic acid-terephthalic acid-butylene glycol (referred to as PBST), polysuccinic acid-adipate-butylene glycol (referred to as PBSA), polymethyl ethylene carbonate (referred to as PPC), poly Hydroxy fatty acid ester (PHA for short), and polyethylene adipate (PEA for short).

In another embodiment, the aliphatic polyester is selected from glycolic acid homopolymers or glycolic acid copolymers.

In another embodiment, the material further contains a bonding layer between two adjacent structural layers.

In a second aspect of the present invention, there is provided a method for preparing the material provided by the present invention as described above, the method comprising the steps of:

(1) Forming a degradable resin into a structural layer; and

(2) A melt of degradable resin is injected between adjacent structural layers after stacking, and then compression molding is performed to form the material provided by the present invention as described above.

In the third aspect of the present invention, an application of the material provided by the present invention as described above is provided.

Accordingly, the present invention provides a new idea that can accurately control the properties (eg, mechanical properties, degradation properties, heat resistance properties, etc.) of degradable polymer materials.

Description of drawings

Figure 1 shows the cross section of the composite structure of sheet and roll made of the material provided by the present invention.

Figure 2 shows a schematic diagram of the material obtained in Example 1 or 2.

Figure 3 shows a schematic diagram of the material obtained in Example 4.

Figure 4 shows a schematic representation of the materials obtained in Examples 5 and 6.

detailed description

After extensive and in-depth research, the inventor found that the degradable resin with crystallinity is made into a multi-layer structure, and the crystallinity between two adjacent layers is different. By controlling the crystallinity of each layer, the distribution of the crystalline region can be achieved. The elongation at break and impact strength of the degradable polymer materials thus obtained can be significantly improved. At the same time, since the degradation performance of the material is related to the crystallinity to a certain extent, it can be adjusted based on the distribution of the crystalline region. To influence the degradation time of the final material, the degradation time of the final material can be controlled more accurately. On this basis, the present invention has been completed.

Specifically, the present invention provides a material having a plurality of structural layers, the structural layers are formed of degradable resin, and the crystallinity of adjacent structural layers is different.

Each structural layer in the material provided by the present invention may be formed of the same degradable resin, or may be formed of different degradable resins.

In one embodiment of the present invention, the crystallinity of adjacent structural layers in the material differs by 0.1-72%, such as, but not limited to, 0.1-1%, 0.2-2.5%, 0.3-1.8%, 2-10%, 3-70%, 4-15%, 5-17%, 8-40%, 9-19%, 10-22%, 13-60%, 0.5-20%, 0.1-70%, etc.

In an embodiment of the present invention, the height of the longitudinal section of the material is generally 10 micrometers to 50 centimeters, and the number of structural layers contained therein is not limited.

As used in the present invention, "degradable resin" refers to a polymer material having a hydrolyzable functional group, and the hydrolyzable functional group is selected from one or more of the following: ester group, amide group, hydroxyl group, Carboxyl, anhydride and carbamate groups.

In some embodiments of the present invention, the degradable resin is selected from the group consisting of aliphatic polyester, polyhydroxyester ether, polyhydroxyalkanoate, polyanhydride, polyamino acid, polyethylene oxide, polyphosphazene, polyetherester, Any one or any copolymer, mixture, derivative or combination of polyamide ester, polyamide, sulfonated polyester, thermoplastic polyester elastomer or thermoplastic polyurethane elastomer.

The aliphatic polyester includes at least one of hydroxycarboxylic acid-based aliphatic polyester, lactone-based aliphatic polyester, and glycol dicarboxylic acid-based aliphatic polyester.

In some embodiments of the present invention, the aliphatic polyester is selected from glycolic acid homopolymers, glycolic acid copolymers, polylactic acid and its copolymers, poly-ε-caprolactone (PCL for short), polybutylene glycol Ethylene glycol ester (PES for short), polybutylene succinate (PBS for short), polybutylene adipate-terephthalate (PBAT), polysuccinic acid-terephthalate Formate-butylene glycol ester (referred to as PBST), polysuccinic acid-adipate-butylene glycol ester (referred to as PBSA), polymethyl ethylene carbonate (referred to as PPC), polyhydroxy fatty acid ester (referred to as PHA) , and at least one of polyethylene adipate (PEA for short).

In a preferred embodiment of the present invention, the aliphatic polyester is selected from glycolic acid homopolymers or glycolic acid copolymers.

As a preferred technical solution, in the glycolic acid copolymer, the proportion of glycolic acid repeating units can be selected to be more than 10wt%, preferably more than 50wt%, more preferably more than 70wt%, still more preferably more than 85wt%, most preferably 90 wt% or more.

The glycolic acid copolymer contains, in addition to glycolic acid repeating units, hydroxycarboxylic acid units (for example, lactic acid units, 3-hydroxypropionic acid units, 3-hydroxybutyric acid units, 4-hydroxybutyric acid units, 6 -Hydroxycaproic acid unit, etc.), lactone-based units (for example, β-propiolactone unit, β-butyrolactone unit, γ-butyrolactone unit, ε-caprolactone unit, etc.), carbonate-based units ( For example, at least one of trimethylene carbonate units, etc.), and amide-based units (eg, ε-caprolactam units, etc.).

As a preferred technical solution, the glycolic acid copolymer is selected from glycolic acid-lactic acid copolymers.

Since the crystallization rate of the polymer is also affected by the size of the molecular weight, under the same conditions, different crystallization rates often lead to different final crystallinity of the polymers. Based on this, each structural layer in the material of the present invention can be made of degradable resins with different relative molecular weights (eg, glycolic acid homopolymer or glycolic acid-lactic acid copolymer).

In addition, each structural layer in the material of the present invention can also be made of a degradable resin (for example, glycolic acid homopolymer or glycolic acid-lactic acid copolymer) of the same relative molecular mass.

The relative molecular mass of the glycolic acid homopolymer used in the present invention can be selected to be 10-1 million, preferably 20,000-600,000, more preferably 30,000-400,000, most preferably 40,000-300,000; The relative molecular mass of the glycolic acid-lactic acid copolymer can be selected to be 10,000-300,000, preferably 10,000-200,000, and more preferably 20,000-150,000.

The crystallinity of the structural layer formed by the degradable resin can be controlled using the conventional technical means of the present invention, for example, but not limited to, by adjusting the corresponding process conditions (for example, cooling temperature, cooling rate) that can affect the crystallization when forming each structural layer. , tensile stress, etc.) to achieve. For example, but not limited to, using degradable resin (for example, glycolic acid homopolymer), with existing extrusion molding, calendering molding or blow molding and other molding methods, the cooling temperature is controlled to be 0-230 ° C, and the cooling rate is 0.1 -80°C/min, the structural layers A, B, C and D with different crystallinity are processed respectively, so that the crystallinity of the A layer is about 70%, the crystallinity of the B layer is about 62%, and the crystallinity of the C layer is about 56%, the crystallinity of the D layer is about 41% and so on.

As used in the present invention, "crystallinity" refers to the proportion of crystalline regions in a polymer, which can be determined by density method or thermal analysis method. For example, the DSC method can be used to measure the crystallinity of each layer, that is, the crystallinity of the sample can be calculated by the ratio of the heat absorbed by the melting of the sample crystal region to the heat of fusion of a fully crystallized sample or a standard sample with known crystallinity. This is a conventional testing method in the field, and will not be repeated here.

There are bonding layers between the structural layers of the material provided by the present invention, so that the structural layers are connected, and the layers are compounded together after compression molding, so that the material provided by the present invention is integrated.

The bonding layer in the material provided by the present invention is also formed using degradable resin, which can be the same or different degradable resin as that of the structural layer, preferably the same degradable resin as one of the adjacent structural layers.

The crystallinity of the bonding layer in the material provided by the present invention and the crystallinity of one of the adjacent structural layers may differ by 0-72%, such as, but not limited to, 0.1-1%, 0.2-2.5%, 0.3 -1.8%, 2-10%, 3-70%, 4-15%, 5-17%, 8-40%, 9-19%, 10-22%, 13-60%, 0.5-20%, 0.1 -70% etc. As a preferred embodiment, the difference between the crystallinity of the bonding layer and the crystallinity of one of the adjacent structural layers is generally not more than 10%.

In one embodiment of the present invention, a melt of degradable resin is injected between two adjacent structural layers, and a bonding layer is formed after cooling.

As used in the present invention, "melt" refers to a state in which a polymer is between the flow temperature or melting point and the decomposition temperature, and can move against intermolecular forces.

The bonding layer in the material provided by the present invention can be completely attached to the surfaces of the two adjacent structural layers, or can be dispersed on the surfaces of the adjacent structural layers, as long as the structural layers can be connected. In a preferred embodiment of the present invention, the cross-sectional area of the bonding layer is 30% or more of the surface area of the adjacent structural layer, more preferably 70% or more, and most preferably 90% or more.

As a preferred technical solution, the bonding layer in the material provided by the present invention can be selected to be in complete contact with the surfaces of the two adjacent structural layers. In this case, there is no sufficient influence between the bonding layer and the structural layer. Distinguishing properties of the physical and/or chemical properties of an entire material.

Based on the above preferred technical solution, in an embodiment of the present invention, each structural layer and the bonding layer between two adjacent structural layers can be made of the same degradable resin. In this case, the bonding layer The structural layer may have substantially the same properties, with no essential difference between the two. In view of the above situation, further description is made below with reference to accompanying drawing 2:

The degradable polymer material shown in Figure 2 has a multi-layer structure, and the structural layers A, B, C, D and the bonding layers E, F, and G can be made of, for example, glycolic acid homopolymers. The prepared structural layers The crystallinity of A may be, for example, about 70%, the crystallinity of structure layer B may be, for example, about 62%, the crystallinity of structure layer C may be, for example, about 56%, and the crystallinity of structure layer C may be, for example, about 41%. The bonding layers E, F, G may respectively have the same or different crystallinity than one of the two adjacent structural layers. Here, the case of the crystallinity of the bonding layer E will be described as an example:

For example, in the first case: the crystallinity of the bonding layer E can be the same as that of the structural layer A, then the bonding layer E is equivalent to belonging to the structural layer A, that is, the bonding layer E can be regarded as a part of the structural layer A;

For example, in the second case: the crystallinity of the bonding layer E can be the same as that of the structural layer B, then the bonding layer E is equivalent to belonging to the structural layer B, that is, the bonding layer E can be regarded as a part of the structural layer B;

For example, in the third case: the crystallinity of the bonding layer E is different from that of the structural layers A and B. At this time, the bonding layer E is equivalent to becoming a structural layer by itself, that is, the bonding layer E can be regarded as a , B has an equivalent structural layer E on the structure of the entire degradable polymer material.

The above description regarding the crystallinity of the bonding layer E applies to the bonding layers F and G in the same way.

The thickness of each layer (eg, between structural layers, between bonding layers, or between structural layers and bonding layers) in the material provided by the present invention may be the same or different. Preferably the thickness of each layer is the same.

Each layer (including the structural layer and the bonding layer) in the material provided by the present invention may have a regular shape or an irregular shape (for example, a shape with a thick middle and a thin perimeter or a shape with a thin middle and a thick perimeter, or a shape with shape like a wavy cross-section, etc.). The shapes of each layer (eg, between the structural layer and the structural layer, between the bonding layer and the bonding layer, or between the structural layer and the bonding layer) can be the same or different; preferably the shapes of the layers are the same.

The molecular weight of each layer (including the structural layer and the bonding layer) in the material provided by the present invention may be the same or different.

The material provided by the present invention can be prepared by the following steps:

The first step is to make the degradable resin form a structural layer with a certain degree of crystallinity;

In the second step, the melt of degradable resin is injected between adjacent structural layers after stacking, and then the material provided by the present invention is obtained by compression molding.

In the first step above, structural layers with different degrees of crystallinity can be separately processed by molding methods such as extrusion molding, calendering molding, or blow molding well-known in the art.

In one embodiment of the present invention, for example, for glycolic acid polymer, a calendering molding method can be used, and the cooling temperature is controlled to be 0-230° C., and the cooling rate is 0.1-80° C./min, forming a crystallinity of about 25-230° C. 72% structural layers.

In the above second step, the structural layers may be stacked in any manner. In an embodiment of the present invention, the structural layers are sequentially stacked from bottom to top by means of lead-in parts. The lead mold part includes a lead mold part body, and the lead mold part body is provided with grooves and/or holes for guiding and positioning each layer of material. There are no special requirements on the selection of the shape, size, position and number of the grooves and/or holes, as long as the uniform stacking of each layer of material is sufficient.

In an embodiment of the present invention, in the second step above, the injection time of the melt of the degradable resin is controlled to be 2-40 seconds, and then compression molding is performed. The process conditions of the compression molding can be: preheating time is 2-10 minutes, molding time is 2-15 minutes, molding temperature: 0-260°C, preferably 100-250°C, most preferably 210-240°C ; The molding pressure is 0.5-2MPa; the cooling time is 2-4 minutes, and the cooling temperature is 0-230°C, preferably 10-150°C, and most preferably 30-120°C.

In a preferred embodiment of the present invention, the mass injection rate of the melt can be controlled to be about 1-10 grams per second.

The second step above can be done in the following two ways:

The first way: when there are more than 3 stacked structural layers, after injecting the melt of degradable resin between all two adjacent structural layers, press molding is performed under one process condition, and each bonding layer is obtained. The crystallinity is the same or similar.

The second way: when it is desired to obtain more than 3 structural layers of the material, first inject a melt of degradable resin between two adjacent structural layers, and use a certain process for molding to obtain the corresponding crystallinity. Bonding layers, and then stacking another structural layer on one of the structural layers, injecting a melt of degradable resin between the newly formed adjacent structural layers, and using a modified or unchanged process for compression molding to obtain the corresponding crystallinity the bonding layer. So on and so forth. In this way, each bonding layer with a relatively large difference in crystallinity can be obtained.

The materials provided by the present invention can be processed by machining such as cutting, drilling, cutting, etc. to form profiles with desired shapes, including but not limited to plates, sheets, bars, strip profiles, strip profiles, disc profiles, Wire, etc., can also be made into a coil with a cross-section similar to the shape of tree rings, and can also be made into a composite structure of the above two profiles, for example, in a coil (for example, it has a shape similar to that of tree years. A hollow cavity can be reserved or preset at the center of the concentric circles of the cross-section of the wheel profile, and multilayer sheets can be embedded in the hollow cavity to obtain a composite structure of sheets and rolls, see Figure 1 . It can also be made into films such as barrier films, packaging films, and mulching films.

The above features mentioned in the present invention or the features mentioned in the embodiments can be combined arbitrarily. All the features disclosed in this specification can be used in combination with any combination, and as long as there is no contradiction in the combination of these features, all possible combinations should be considered within the scope of this specification. Each feature disclosed in the specification may be replaced by any alternative feature serving the same, equivalent or similar purpose. Therefore, unless otherwise stated, the disclosed features are only general examples of equivalent or similar features.

The main advantages of the present invention are:

1. The elongation at break and impact strength of the material provided by the present invention can be significantly improved.

2. The material provided by the present invention can easily and effectively control the degradation rate of the material, and can control the degradation time more accurately.

3. The present invention can control the heat deformation temperature of the final material by adjusting the crystallinity of each layer, without adding additives such as heat stabilizers, antioxidants, heat-resistant inorganic fillers, etc., to achieve heat resistance to the final material. Sexual flexibility.

The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and provides a detailed implementation manner and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments. All other embodiments obtained by a person of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The endpoints of ranges and any values disclosed herein are not limited to the precise ranges or values, which are to be understood to encompass values proximate to those ranges or values. For ranges of values, the endpoints of each range, the endpoints of each range and the individual point values, and the individual point values can be combined with each other to yield one or more new ranges of values that Ranges should be considered as specifically disclosed herein. For example, "a range from 1 to 10" should be understood to mean every and every possible number consecutively between about 1 and about 10. Thus, even if a specific data point within a range, or even no data point within the range is specifically identified or refers only to a small number of specific points, it should be understood that any and all data points within the range are considered to be specifically stated. As used herein, when the term "about" is used to modify a numerical value, it means a tolerance for error of measurement within ±5% of the numerical value.

The technical solution of the present invention is further described below through specific examples. Unless otherwise specified in the present invention, the raw materials used are all commercially available products.

The degradability test method involved in the following examples adopts the following test method to test the degradability of the sample material (machining can be used, and the material to be tested can be processed into a sample with a length of 20 mm × height 20 mm × width 20 mm for degradation test). test.

Degradability test method:

Step 1): take 3 samples, weigh them, record the initial mass as M ₀ , then place them in a constant temperature drying oven, and dry them at 60° C. for 24 hours;

Step 2): Place the 3 dried samples in 3 beakers containing 75°C clean water, and immerse each sample completely in the clean water, and then place the 3 beakers in 3 same specifications. in the constant temperature and humidity test chamber (the temperature is set to 75 ℃);

Step 3): at intervals, take out the samples in 3 constant temperature and humidity test chambers, wash them with distilled water, put them in a constant temperature drying chamber, dry them at 105°C for 2 hours and weigh them, and record the remaining samples. The mass is M', and then the samples are placed in the corresponding beakers to continue the degradation experiment;

Step 4): Calculate the degradation rate R _d , the calculation formula is as follows:

R _d =(M ₀ -M')/M ₀ ×100%.

When the calculated degradation rate R _d reaches more than 95%, the experiment is stopped.

Note: Regarding the selection of sampling interval in step 3), in the initial stage of the degradation experiment, the sampling interval can be longer (for example, the interval is 4 hours, or 6 hours, etc.), and it can be appropriately shortened in the middle and late stages of the degradation experiment Interval time (eg, 2 hour interval, 1 hour interval, or 30 minute interval, etc.).

In addition, in step 3), for the situation that the original shape of the sample in the beaker has basically disappeared, the following methods can be used to measure the quality:

Take out the beaker in the constant temperature and humidity test box, let it stand, and then extract the supernatant to separate the remaining solid phase, wash the separated remaining solid phase with distilled water, and then put it into a constant temperature drying box and dry it at 105 ° C Weigh after 2 hours and record the remaining solid phase mass as M'.

The heat deformation temperature test involved in the following examples is based on GB/T 1633-2000, and the heat deformation temperature-Vicat softening point tester is used to test the heat deformation temperature of the material.

The sample used in the test is a long strip with a rectangular cross-section. The surface of the sample is flat and smooth, without bubbles, sawing marks or cracks and other defects. The size of the material sample to be tested is: length 120mm × height 15mm × width 10mm.

The heat transfer medium used in the test is methyl silicone oil, the heating rate is controlled at 120 °C/hour, the center distance between the two sample supports is 100 mm, and a vertical load is applied to the sample at the midpoint of the support. The contact part of the sample is a semicircle with a radius of (3±0.2) mm. During the experiment, the maximum bending normal stress of the sample after being loaded is 4.6kg/cm ² .

Example 1

Using the glycolic acid homopolymer with a relative molecular mass of 243,000, using the calendering method, controlling the cooling temperature to 130 ° C and the cooling rate to 1 ° C/min, a structural layer A with a crystallinity of about 70% can be obtained. The relative molecular mass of 24.3 Wan's glycolic acid homopolymer adopts the extrusion molding method, and the cooling temperature is controlled to be 100 ° C and the cooling rate is 3 ° C/min, and the structural layer B with a crystallinity of about 62% can be obtained. The homopolymer adopts the calendering molding method, the cooling temperature is controlled to be 90 °C, and the cooling rate is 10 °C/min, and a structural layer C with a crystallinity of about 56% can be obtained. The molding method is used, and the cooling temperature is controlled to be 80 °C and the cooling rate is 25 °C/min, and a structural layer D with a crystallinity of about 41% can be obtained;

The structural layer A and the structural layer B are stacked by the lead mold; the melt of glycolic acid homopolymer with a relative molecular mass of 243,000 is injected between the structural layers A and B, and then the process condition I is used for compression molding, and the crystallinity is obtained. about 65% of the E layer;

The structural layer C is stacked on the structural layer B by the lead mold, and then a melt of glycolic acid homopolymer with a relative molecular mass of 243,000 is injected between the structural layers B and C, and then the process condition II is used for compression molding to obtain crystals. degree of about 60% of the F layer;

The structural layer D is stacked on the structural layer C through the lead-molding part, and then the melt of glycolic acid homopolymer with a relative molecular mass of 243,000 is injected between the structural layers C and D, and then the process condition III is used for compression molding to obtain crystals. The degree of G layer is about 42%, and the material shown in Figure 2 is obtained;

Among them, the process conditions I, II and III are shown in Table 1:

Table 1

project	Preheat time	Molding temperature	Molding pressure	Molding time	cooling temperature
Process conditions I	5 minutes	210℃	1.2MPa	6 minutes	150℃
Process condition II	5 minutes	210℃	1.2MPa	6 minutes	136℃
Process conditions Ⅲ	5 minutes	210℃	1.2MPa	6 minutes	120℃

Example 2

Using the glycolic acid homopolymer with a relative molecular mass of 124,000, the calendering method is used, the cooling temperature is controlled to 150 ° C, and the cooling rate is 0.5 ° C/min, and a structural layer A with a crystallinity of about 70% can be obtained. The relative molecular mass of 18.5 Wan's glycolic acid homopolymer adopts the extrusion molding method, the cooling temperature is controlled to 120°C, and the cooling rate is 2°C/min, and the structural layer B with a crystallinity of about 62% can be obtained. The homopolymer adopts the calendering method, the cooling temperature is controlled to be 100 °C, and the cooling rate is 10 °C/min, and a structural layer C with a crystallinity of about 56% can be obtained. A molding method is developed, the cooling temperature is controlled to be 75°C, and the cooling rate is 15°C/min, and a structural layer D with a crystallinity of about 41% can be obtained;

The structural layer A and the structural layer B are stacked by the lead-molding member; the melt of glycolic acid homopolymer with a relative molecular mass of 156,000 is injected between the structural layers A and B, and then the process conditions I in Example 1 are used for molding. , obtaining an E layer with a crystallinity of about 65%;

The structural layer C is stacked on the structural layer B through the lead-in part, and then a melt of glycolic acid homopolymer with a relative molecular mass of 201,000 is injected between the structural layers B and C, and then the process conditions II in Example 1 are used to carry out the process. Compression molding to obtain an F layer with a crystallinity of about 60%;

The structural layer D is stacked on the structural layer C through the lead-in, and then a melt of glycolic acid homopolymer with a relative molecular mass of 275,000 is injected between the structural layers C and D, and then the process condition III in Example 1 is used to carry out the process. Compression molding yielded a G layer with a crystallinity of about 42% and a material as shown in Figure 2 was obtained.

Example 3

Using glycolic acid homopolymer with a relative molecular mass of 243,000, referring to the process of obtaining structural layer A in Example 1, a single-layer material with a crystallinity of about 70% was obtained, and its thickness was the same as that obtained in Example 1 or 2, as shown in Figure 2 Materials are the same.

According to the GB/T 1042 method, the material shown in Figure 2 obtained in Examples 1 and 2 and the single-layer material obtained above were tested for the material elongation at break.

According to the GB/T 1043 method, the material shown in Figure 2 obtained in Examples 1 and 2 and the single-layer material obtained above were tested for material impact strength.

The results are shown in Tables 2 and 3.

Table 2

table 3

Example 4

Using a glycolic acid homopolymer with a relative molecular mass of 168,000, a method similar to Example 1 was used to obtain the material shown in Figure 3, which has structural layer A, structural layer B and structural layer C, and bonding layers E and F .

Each material obtained by the method of Example 4 and Comparative Examples 1 and 2 were tested using the degradability test method. The results are shown in Table 4.

Table 4

Note: Comparative Example 1 in Table 4 is a C-layer single-layer material (without multi-layer structure), and Comparative Example 2 is a C-layer single-layer material with a hydrolysis accelerator (dimethyl oxalate) added (addition of a hydrolysis accelerator) amount is about 0.8 wt%).

The material thicknesses of Comparative Examples 1 and 2 were the same as those of Examples 1-1 to 6.

The results show that, compared with Comparative Example 1, the degradation rates of the materials of Examples 1-1, 1-2 and 1-3 are all faster than those of Comparative Example 1, which may be due to the different materials of Examples 1-1 to 1-3. In the multi-layer structure of crystallinity, the layer with lower crystallinity tends to degrade to a greater extent before the layer with higher crystallinity, and the layer with lower crystallinity may promote water migration during the degradation process. The layer with higher crystallinity penetrates into the layer with higher crystallinity, which is beneficial to accelerate the degradation of the layer with higher crystallinity. Therefore, in terms of macroscopic performance, the materials of Examples 1-1, 1-2, and 1-3 with a multi-layer structure (the crystallinity of two adjacent layers are different) degrade significantly faster than that of Comparative Example 1, which has only a single-layer structure. Material.

Compared with Comparative Example 1, Comparative Example 2 added a hydrolysis accelerator (for example, dimethyl oxalate) that can promote the degradation of the material. It can be seen from the data in Table 3 that although the use of the hydrolysis accelerator can effectively accelerate the degradation of the material, its The degradation rate is not stable. The time required for the three samples to reach a degradation rate of more than 95% in water at 75°C differs greatly. The maximum difference is about 20.2 hours, and the minimum difference is about 9.4 hours. This is not conducive to the realization of the material. Accurate control of degradation time. Different from Comparative Example 2, the degradation rate of the material in Example 1-1 is relatively stable, and the time required for the three samples to reach a degradation rate of more than 95% in water at 75°C differs by no more than 4 hours. The same is true for the materials of Examples 1-2 and 1-3.

Examples 2-6 illustrate that the present invention can control the degradability of the final material by controlling the difference in the crystallinity of each layer, and the difference between the degradation times corresponding to the three samples in each example is not more than 4 hours, This can also indicate that the present invention can achieve relatively accurate regulation of the degradability of the material.

Example 5

The material shown in FIG. 4 is obtained by a method similar to that of Example 1, which has the structural layer A and the structural layer B, and the bonding layer E.

Each material obtained by the method of Example 5 was tested using the degradability test method. The results are shown in Table 5, wherein the structural layer A and the bonding layer E in Examples 7-1 and 7-2 are glycolic acid-lactic acid copolymers (molecular weight is about 168,000), and structural layer B is glycolic acid homopolymer (molecular weight is about 168,000). is about 85,000); the structural layers A and B and the bonding layer E in Example 8 are both glycolic acid-lactic acid copolymers (molecular weight is about 85,000).

table 5

Examples 7-1, 7-2 and 8 illustrate that the present invention can control the degradability of the final material by controlling the difference in crystallinity of each layer, and the difference in degradation time corresponding to the three samples in each example It is not more than 4 hours, indicating that the present invention can achieve relatively accurate regulation of the degradability of the material.

Example 6

The material shown in FIG. 4 is obtained by a method similar to that of Example 1, which has the structural layer A and the structural layer B, and the bonding layer E.

Each material obtained by the method of Example 6 was tested using the heat deflection temperature test method. The results are shown in Table 6. In Examples 9-1 to 9-3, the structural layers A, B and the bonding layer E are all glycolic acid homopolymers (molecular weight is about 214,000).

Table 6

The results show that, for the material provided by the present invention, the thermal deformation temperature of the final material can be regulated by adjusting the crystallinity of each layer, and then the heat resistance of the final material can be effectively regulated.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the scope of the essential technical content of the present invention. The essential technical content of the present invention is broadly defined within the scope of the claims of the application, and any technical entity completed by others Or method, if it is exactly the same as that defined in the scope of the claims of the application, or an equivalent change, it will be deemed to be covered by the scope of the claims.

Claims (10)

1. A material, characterized in that the material contains at least two structural layers, and the crystallinity of adjacent structural layers is different; the structural layers are formed of degradable resin.
2. The material of claim 1, wherein the crystallinity of adjacent structural layers differs by 0.1-72%.
3. The material of claim 1, wherein each structural layer is formed of the same or different degradable resins.
4. The material according to claim 1, wherein the degradable resin has a hydrolyzable functional group, and the hydrolyzable functional group is selected from one or more of the following: ester group, amide group, Hydroxyl, carboxyl, anhydride and carbamate groups.
5. The material according to claim 1, wherein the degradable resin is selected from one or more of the following copolymers, mixtures, derivatives or combinations: aliphatic polyester, polyhydroxyester ether, poly Hydroxyalkanoates, polyanhydrides, polyamino acids, polyethylene oxides, polyphosphazenes, polyetheresters, polyesteramides, polyamides, sulfonated polyesters, thermoplastic polyester elastomers, thermoplastic polyamide elastomers, and thermoplastic polyurethanes Elastomer.
6. The material according to claim 5, wherein the aliphatic polyester is selected from one or more of the following: glycolic acid homopolymer, glycolic acid copolymer, polylactic acid and its copolymers, polyglycolic acid -ε-caprolactone, polyethylene succinate, polybutylene succinate, polybutylene adipate-terephthalate, polysuccinate-terephthalate- Butylene glycol ester, polysuccinate-adipate-butylene glycol ester, polymethylethylene carbonate, polyhydroxy fatty acid ester, and polyethylene adipate.
7. 6. The material of claim 5, wherein the aliphatic polyester is selected from glycolic acid homopolymers or glycolic acid copolymers.
8. The material according to any one of claims 1-7, characterized in that, the material further comprises a bonding layer between two adjacent structural layers.
9. A method for preparing a material according to any one of claims 1-8, wherein the method comprises the steps of:

   (1) making the degradable resin form a structural layer;

   (2) The melt of degradable resin is injected between adjacent structural layers after stacking, and then the material according to any one of claims 1-8 is formed by compression molding.
10. 1. Use of a material as claimed in any one of claims 1-8.

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