CN110835448A - Polyvinyl acetal foam material, preparation method thereof and cervical dilation device - Google Patents
Polyvinyl acetal foam material, preparation method thereof and cervical dilation device Download PDFInfo
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- CN110835448A CN110835448A CN201911248917.2A CN201911248917A CN110835448A CN 110835448 A CN110835448 A CN 110835448A CN 201911248917 A CN201911248917 A CN 201911248917A CN 110835448 A CN110835448 A CN 110835448A
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
- C08J9/26—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof by elimination of a solid phase from a macromolecular composition or article, e.g. leaching out
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/02—Surgical instruments, devices or methods, e.g. tourniquets for holding wounds open; Tractors
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/42—Gynaecological or obstetrical instruments or methods
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F8/00—Chemical modification by after-treatment
- C08F8/28—Condensation with aldehydes or ketones
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B2017/00831—Material properties
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B2017/00831—Material properties
- A61B2017/00862—Material properties elastic or resilient
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/42—Gynaecological or obstetrical instruments or methods
- A61B2017/4216—Operations on uterus, e.g. endometrium
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2201/00—Foams characterised by the foaming process
- C08J2201/04—Foams characterised by the foaming process characterised by the elimination of a liquid or solid component, e.g. precipitation, leaching out, evaporation
- C08J2201/046—Elimination of a polymeric phase
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2329/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal, or ketal radical; Hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Derivatives of such polymer
- C08J2329/14—Homopolymers or copolymers of acetals or ketals obtained by polymerisation of unsaturated acetals or ketals or by after-treatment of polymers of unsaturated alcohols
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2403/00—Characterised by the use of starch, amylose or amylopectin or of their derivatives or degradation products
- C08J2403/02—Starch; Degradation products thereof, e.g. dextrin
Abstract
The invention discloses a polyvinyl acetal foam material, a preparation method thereof and a cervical dilatation device; the preparation method comprises the following steps: (1) preparation of polyvinyl acetal cellular foam: mixing the raw materials, and reacting to obtain the polyvinyl acetal porous foam; the raw materials consist of polyvinyl alcohol, water, a cross-linking agent, a pore-forming agent and an acid catalyst; (2) cutting; (3) drying; (4) compression molding; the polyvinyl acetal foam material has the advantages of smooth macroscopic surface, no defect, high surface toughness, safe use, good water absorption, high tensile strength and good resilience, and can be used as a cervical dilating rod body for a cervical dilating device.
Description
Technical Field
The invention relates to the technical field of medical instruments, in particular to a polyvinyl acetal foam material, a preparation method thereof and a cervical dilatation device.
Background
The center of the cervix is a long fusiform lumen with a slightly flattened front and back, which is mainly composed of connective tissue and also contains smooth muscle fibers, blood vessels and elastic fibers. When in gynecological operations such as ring removal, ring placement, induced abortion, uterine curettage and the like, a cervical dilator is usually required to dilate the cervical orifice during the operation because the cervical orifice is tight, so as to achieve the purpose of the operation. Clinically, the cervix uteri is dilated by a physical rigid dilation mode of a cervix uteri dilating rod with different diameters made of metal or rigid plastics, which often causes long operation time, great pain to patients and easily causes adverse reactions such as uterine injury, embryo injury, bleeding and the like.
At present, in order to realize the slow expansion of the cervix, relieve the pain of patients and reduce the operation difficulty and the occurrence of complications, a slow expansion type disposable cervix expansion rod with self-expansion performance is prepared by utilizing the water absorption expansion characteristic of a high polymer material. However, the expansion rod made of the self-expanding material adopted at present has the problem of low water absorption expansion rate, and is difficult to meet the clinical use requirement.
Disclosure of Invention
In view of the above, the present application provides the polyvinyl acetal foam material, the preparation method thereof and the cervical dilatation device of the present invention; the polyvinyl acetal foam material has smooth macroscopic surface, no defect, strong surface layer, safe use, good water absorption, larger tensile strength and good resilience, and can be used as a cervical dilating rod body for a cervical dilating device.
In order to solve the technical problems, the technical scheme provided by the application is a preparation method of a polyvinyl acetal foam material, which comprises the following steps:
(1) preparation of polyvinyl acetal cellular foam: mixing the raw materials, and reacting to obtain the polyvinyl acetal porous foam; the raw materials consist of polyvinyl alcohol, water, a cross-linking agent, a pore-forming agent and an acid catalyst; the pore-forming agent is potato starch and corn starch, and the weight ratio of the potato starch to the corn starch is 3.5-4.5: 1; the cross-linking agent is formaldehyde or paraformaldehyde; the dosage of the water is 10-15 ml per 1g of polyvinyl alcohol, the dosage of the cross-linking agent is 1.0-1.5 ml per 1g of polyvinyl alcohol, the dosage of the pore-forming agent is 0.45-0.55 g per 1g of polyvinyl alcohol, and the dosage of the acidic catalyst is more than or equal to 1ml per 1g of polyvinyl alcohol;
(2) cutting;
(3) drying;
(4) and (4) compression molding.
Preferably, the polyvinyl alcohol is polyvinyl alcohol 1788.
Preferably, the crosslinking agent is formaldehyde.
Preferably, the crosslinking agent is 37 to 40 wt% formaldehyde.
Preferably, the acidic catalyst is selected from one or more of hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid and oxalic acid.
Preferably, the acidic catalyst is sulfuric acid.
Preferably, the acidic catalyst is 50 wt% sulfuric acid.
Preferably, the reaction is a crosslinking reaction with a crosslinking temperature of 50-53 ℃.
Preferably, the weight ratio of potato starch to corn starch is 4: 1.
Preferably, the amount of the water is 13ml per 1g of polyvinyl alcohol, the amount of the cross-linking agent is 1.2ml per 1g of polyvinyl alcohol, the amount of the pore-forming agent is 0.5g per 1g of polyvinyl alcohol, and the amount of the acid catalyst is 1ml per 1g of polyvinyl alcohol.
Preferably, the process for preparing the polyvinyl acetal porous foam specifically comprises the following steps:
A. mixing polyvinyl alcohol and water, stirring, and heating at 80-110 ℃ until the polyvinyl alcohol is completely dissolved; the water consumption is 10-15 ml per 1g of polyvinyl alcohol;
B. controlling the temperature to be 53-78 ℃, adding the pore-forming agent, stirring, and reacting for 5-20 min; the pore-forming agent is potato starch and corn starch, and the weight ratio of the potato starch to the corn starch is 3.5-4.5: 1; the cross-linking agent is formaldehyde or paraformaldehyde; the amount of the pore-forming agent is 0.45-0.55 g per 1g of polyvinyl alcohol;
C. controlling the temperature to be 50-53 ℃, adding the cross-linking agent, stirring, and reacting for 5-20 min; the cross-linking agent is formaldehyde or paraformaldehyde; the dosage of the cross-linking agent is 1.0-1.5 ml per 1g of polyvinyl alcohol;
D. controlling the temperature to be 50-53 ℃, adding the acidic catalyst, stirring, and reacting for 10-25 min; the dosage of the acidic catalyst is more than or equal to 1ml per 1g of polyvinyl alcohol;
E. preserving the heat for 6 to 12 hours at the temperature of between 50 and 53 ℃;
F. and (3) post-treating the polyvinyl acetal porous foam until the pH value is 6-7, and removing the residual formaldehyde.
Preferably, the process for preparing the polyvinyl acetal porous foam specifically comprises the following steps:
A. mixing polyvinyl alcohol and water, stirring, and heating at 97 deg.C until polyvinyl alcohol is completely dissolved; the dosage of the formaldehyde is 1.0-1.5 ml per 1g of polyvinyl alcohol;
B. controlling the temperature to be 67 ℃, adding the pore-forming agent, stirring, and reacting for 5-20 min; the pore-forming agent is potato starch and corn starch, and the weight ratio of the potato starch to the corn starch is 3.5-4.5: 1; the cross-linking agent is formaldehyde or paraformaldehyde; the dosage of the pore-forming agent is 1.0-1.5 ml per 1g of polyvinyl alcohol;
C. controlling the temperature to be 53 ℃, adding the cross-linking agent, stirring, and reacting for 5-20 min; the cross-linking agent is formaldehyde or paraformaldehyde; the dosage of the cross-linking agent is 1.0-1.5 ml per 1g of polyvinyl alcohol;
D. controlling the temperature to be 50 ℃, adding the acidic catalyst, stirring, and reacting for 10-25 min; the dosage of the acidic catalyst is 0.5-1.2 ml per 1g of polyvinyl alcohol;
E. preserving the heat at 50 ℃ for 6-12 hours;
F. and (3) post-treating the polyvinyl acetal porous foam until the pH value is 6-7, and removing the residual formaldehyde.
Preferably, the step F specifically includes: and (3) treating the polyvinyl acetal porous foam by using an alkaline solution until the pH value is 6-7, and removing the formaldehyde residue by using hydrogen peroxide.
Preferably, the alkaline solution is an aqueous sodium hydroxide solution.
Preferably, the step (2) specifically comprises: controlling the water content of the polyvinyl acetal porous foam to be 40-60 wt%, and performing freezing cutting
Preferably, the step (2) specifically comprises: centrifuging the polyvinyl acetal porous foam, adding water until the water content of the polyvinyl acetal porous foam is 40-60 wt%, and freezing and cutting;
preferably, the freezing and cutting process specifically comprises: freezing at 15 deg.C for >8h, and cutting.
Preferably, the drying process is air drying or pulse vacuum sterilization drying.
Preferably, the drying process is specifically pulse vacuum sterilization drying.
Preferably, the pulse vacuum sterilization drying specifically comprises: carrying out pulse vacuum sterilization at 40-50 ℃ and-75-60 kpa for 60-90 min.
Preferably, the forced air drying process specifically comprises: and (3) drying by blast air at 40-60 ℃ for 4-10 h.
Preferably, the forced air drying process specifically comprises: air-blast drying at 60 deg.C for 4 h.
Preferably, the compression molding process specifically comprises: and (4) compression molding by adopting a hydraulic press.
Preferably, the compression molding process specifically comprises: pressing into rod shape by hydraulic press.
The invention also provides a polyvinyl acetal foam material prepared by the preparation method.
Preferably, the polyvinyl acetal foam material has an acetalization degree of: the degree of acetalization of polyvinyl formal is: 55 to 70 percent.
Preferably, the pore size of the polyvinyl acetal foam material is 0.02-1.00 mm.
Preferably, the water absorption multiple of the polyvinyl acetal foam material is as follows: the weight m of the polyvinyl formal porous foam after completely absorbing water and the constant weight after dryingQuantity m1Calculating the water absorption times according to the weight ratio
The specific water absorption times are as follows: 9-13 times.
The present invention also provides a cervical dilation apparatus comprising: the cervical dilation rod body; the cervical dilating rod body is the polyvinyl acetal foam material prepared by the preparation method.
Preferably, the cervical dilator is a cervical dilator or a cervical dilating rod.
Compared with the prior art, the detailed description of the application is as follows:
the preparation method of the polyvinyl acetal foam material comprises the following steps: (1) preparation of polyvinyl acetal cellular foam: mixing the raw materials, and reacting to obtain the polyvinyl acetal porous foam; (2) cutting; (3) drying; (4) and (4) compression molding. The raw materials consist of polyvinyl alcohol, water, a cross-linking agent, a pore-forming agent and an acid catalyst; the polyvinyl acetal foam material has smooth macroscopic surface, no defect, strong surface layer, safe use, good water absorption, higher tensile strength and good resilience, and can be used as a cervical dilating rod body for a cervical dilating device.
According to the invention, the potato starch and the corn starch are compounded to be used as pore-forming agents, and the screening and proportioning are carried out, so that the comprehensive effects of the potato starch and the corn starch are exerted, and the product is ensured to have small density, be spongy, good rebound resilience and good water absorption. In the process of polyvinyl formal, starch in the system expands under acidic conditions to occupy a certain space, and during forming, the starch is dissolved into paste again and hydrolyzed to form pores. The addition temperature of the starch is controlled to avoid, the starch is quickly gelatinized when the temperature is too high, and the obtained product has multiple pores, fine pores, softness and no elasticity; the temperature is not required to be too low, the pore-forming agent cannot expand, the hydrolysis speed is extremely slow, the dissolution is difficult, and the pore-forming rate is reduced.
The acidic catalyst is added to provide acidic conditions for the hydroformylation of polyvinyl alcohol, and plays a role of the catalyst. The dosage of the acid catalyst is controlled, and the condition of incomplete crosslinking under the condition of a small amount of the acid catalyst is avoided.
The dosage of the cross-linking agent is controlled, the formalization degree is increased, and the uniform pore-forming is ensured.
The invention controls the crosslinking temperature, and avoids the problems that the distribution of holes wrapped inside is not uniform, the formaldehyde is seriously volatilized, and the environment is polluted because the temperature is overhigh and the viscosity of the solution is rapidly increased. Avoid the problems of too low temperature and long acetalization time, which causes too long production flow and is not suitable for industrial production.
The invention adopts a method of water-containing freezing cutting after controlling the water content, so that the prepared polyvinyl acetal foam material is used for the cervical dilator, and has smooth surface, safe use and accurate size.
The invention adopts blast drying or pulse vacuum sterilization cabinet for drying, so that the prepared polyvinyl acetal foam material is used for the cervical dilator, and has smooth macroscopic surface, safe use and accurate size.
The invention adopts a hydraulic press for compression, so that the prepared polyvinyl acetal foam material is used for the cervical dilator, and has smooth macroscopic surface, safe use and accurate size and good resilience.
According to the analysis, the water content of the polyvinyl acetal porous foam is controlled to be 40-60 wt%, and a cutting product with smooth edge and small cutting error can be obtained by freezing and cutting, so that the prepared polyvinyl acetal foam material is used for the cervical dilator, and has the advantages of smooth surface, safety in use and accurate size.
The drying is carried out by adopting blast drying or a pulse vacuum sterilization cabinet, so that the deformation and the depression are avoided, the size shrinkage is reduced, and the pulse vacuum sterilization cabinet can realize sterilization; namely, the prepared polyvinyl acetal foam material is used for the cervical dilator by adopting blast drying or pulse vacuum sterilization cabinet for drying, and has smooth macroscopic surface, safe use and accurate size.
The prepared polyvinyl acetal foam material is used for the cervical dilator, and has smooth macroscopic surface, safe use and good size accuracy and resilience.
Detailed Description
In order to make those skilled in the art better understand the technical solution of the present invention, the following detailed description of the present invention is provided with reference to specific embodiments.
Examples 1 to 22
Effect of raw materials on product Properties
A method of making a polyvinyl acetal cellular foam comprising:
(1) mixing polyvinyl alcohol and water, stirring at 200r/min, and heating at 97 deg.C until polyvinyl alcohol is completely dissolved;
(2) controlling the temperature to be 67 ℃, adding the pore-forming agent, stirring at 200r/min, and reacting for 5-20 min;
(3) controlling the temperature to be 53 ℃, adding the cross-linking agent, stirring at 200r/min, and reacting for 5-20 min; the cross-linking agent is formaldehyde or paraformaldehyde;
(4) controlling the temperature to be 50 ℃, adding the acid catalyst, stirring at 200r/min, and reacting for 10-25 min;
(5) preserving the heat at 50 ℃ for 6-12 hours;
(6) and (3) treating the polyvinyl acetal porous foam by using a sodium hydroxide aqueous solution until the pH value is 6-7, and removing the formaldehyde residue by using hydrogen peroxide.
The choice and amount of polyvinyl alcohol, the amount of water, the choice and amount of pore former, and the amount of crosslinker are shown in Table 1.
TABLE 1
Examples 1, 23-29 Effect of temperature conditions (polyvinyl acetal cellular foams) on product Properties
Examples 23 to 29 differ from example 1 only in the temperature conditions in the method for producing porous polyvinyl acetal foam, the polyvinyl alcohol dissolution temperature, the pore former addition temperature, the crosslinking agent addition temperature, the acid catalyst addition temperature, and the holding temperature shown in table 2.
TABLE 2
Examples 30 to 56
Effect of cutting, drying and compression processes on product Properties
A method of preparing a polyvinyl acetal foam material, comprising:
(1) a polyvinyl acetal porous foam was prepared.
(2) Cutting;
(3) drying;
(4) compressing into rod shape;
(5) and (5) performing irradiation sterilization.
Polyvinyl acetal foam material, prepared by the above preparation method.
A cervical dilation apparatus comprising: the cervical dilation rod body; the cervical dilating rod body is a polyvinyl acetal foam material prepared by the preparation method; the cervical dilator is a cervical dilator or a cervical dilating rod.
In examples 30 to 39, the polyvinyl acetal porous foam obtained in example 1 was cut by wet cutting, dry cutting, and freeze cutting, respectively; the freezing cutting specifically comprises the following steps: centrifuging the polyvinyl acetal porous foam of example 1, adding water to the required water content of the polyvinyl acetal porous foam, freezing at 15 ℃ for more than 8h, cutting, wherein specific cutting conditions and test results of the cut product are shown in table 3;
in the embodiments 40 to 53, the vacuum drying oven, the blast drying oven and the pulse vacuum sterilization cabinet are respectively adopted to dry the product cut in the embodiment 35, and the specific drying conditions and the test results of the dried product are shown in table 3;
in examples 54 to 56, the dried products in example 51 were compressed by a tablet press and a hydraulic press, and the specific compression conditions and the test results of the compressed products are shown in table 3.
TABLE 3
According to the analysis, the water content of the polyvinyl acetal porous foam is controlled to be 40-60 wt%, and a cutting product with smooth edge and small cutting error can be obtained by freezing and cutting, so that the prepared polyvinyl acetal foam material is used for the cervical dilator, and has the advantages of smooth surface, safety in use and accurate size.
The drying is carried out by adopting blast drying or a pulse vacuum sterilization cabinet, so that the deformation and the depression are avoided, the size shrinkage is reduced, and the pulse vacuum sterilization cabinet can realize sterilization; namely, the prepared polyvinyl acetal foam material is used for the cervical dilator by adopting blast drying or pulse vacuum sterilization cabinet for drying, and has smooth macroscopic surface, safe use and accurate size.
The prepared polyvinyl acetal foam material is used for the cervical dilator, and has smooth macroscopic surface, safe use and good size accuracy and resilience.
And (3) test results:
first, water absorption
Cutting the polyvinyl acetal porous foam of the examples 1-29 into 10cm by 1.2cm, drying the foam in a forced air drying oven at 50 ℃ for 10 hours, and weighing and recording the foam; drying at 105 deg.C for 3h, weighing at constant weight, recording the weight M, placing the weighed material in a 500ml beaker, completely immersing the material in purified water for 3h, weighing the sponge which has completely absorbed water, and recording the weight M. The results are shown in Table 4.
Second, detection of liquid absorbency
Samples of examples 1-29, which were cut into 5cm by 5cm blocks, were dried in a forced air oven at 50 ℃ for 10 hours and weighed for recording; drying at 105 deg.C for 3h, weighing at constant weight, recording the weight M, placing the weighed material in a 500ml beaker, completely immersing the material in purified water for 3h, weighing the sponge which has completely absorbed water, and recording the weight M. Drying at 105 ℃, weighing and recording, measuring the length, the width and the height by a vernier caliper, respectively measuring five times to obtain an average value, adding the average value into a beaker filled with purified water, completely immersing the beaker in the purified water by a glass rod, completely soaking the beaker in the purified water, and extruding the sponge by the glass rod to completely remove air in the sponge. After weighing the wet sponge, the liquid absorbency was calculated from the constant weight and the amount after water absorption. The test was repeated three times, and the liquid absorbencies of the three tests should be substantially similar, and the results are shown in Table 4.
The absorption of the polyvinyl acetal porous foam liquid prepared by the invention is more than or equal to 4.00 g/g.
Third, surface Density (micrometer)
The polyvinyl acetal porous foams of examples 1 to 29 were tested according to the method specified in GB/T6343-2009, and the results are shown in Table 4.
Fourth, detection of pulling force
The mechanical properties of the polyvinyl acetal porous foams of examples 1-29 were measured, and the results are shown in Table 4.
The tensile force of the prepared polyvinyl acetal porous foam is more than or equal to 12N, and the requirement of ISO7439 on the mechanical property index of each part structure of the intrauterine device is more than or equal to 12N.
Fifthly, detection index of formaldehyde
The residual amount of the polyvinyl acetal porous foam aldehydes in examples 1 to 29 was measured, and the results are shown in table 4.
The aldehyde residual quantity of the polyvinyl acetal porous foam prepared by the invention is less than 5 mg/L.
Sixth, elastic recovery
The elastic recovery rates of the polyvinyl acetal porous foams of examples 1 to 29 and the polyvinyl acetal foam material of example 58 were measured, and the results are shown in Table 4.
The product is squeezed by hand, the recovery rate of the product shape is observed, and if the product can be completely recovered, the elastic recovery rate is 100 percent
Hepta, degree of acetalization, number of pores formed and pore size
The acetalization degree, the pore forming number and the pore size of the polyvinyl acetal porous foams of examples 1 to 29 were measured, and the results are shown in Table 4.
Adding 17% hydroxylamine hydrochloride into polyvinyl formal porous foam under the reflux of isopropanol serving as a solvent, stirring for 3 hours for dissolving, standing overnight, cooling to 15-30 ℃, adding thymol blue, titrating by using 0.5mol sodium hydroxide standard solution, performing a blank test by using yellow blue under the same conditions;
wherein the content of the first and second substances,
m is the concentration of sodium hydroxide
m is the mass of the sample
A is the degree of alcoholysis
v1 volume of sodium hydroxide consumed in sample reagent
v2 is the volume of sodium hydroxide consumed in the blank.
Eighth, appearance form
The appearance of the polyvinyl acetal porous foams of examples 1-29 was observed and examined, and the results are shown in Table 4
TABLE 4
The polyvinyl acetal porous foam raw material consists of polyvinyl alcohol, water, a cross-linking agent, a pore-forming agent and an acid catalyst; the pore-forming agent is potato starch and corn starch, and the weight ratio of the potato starch to the corn starch is 3.5-4.5: 1; the cross-linking agent is formaldehyde or paraformaldehyde; the dosage of the water is 10-15 ml per 1g of polyvinyl alcohol, the dosage of the cross-linking agent is 1.0-1.5 ml per 1g of polyvinyl alcohol, the dosage of the pore-forming agent is 0.45-0.55 g per 1g of polyvinyl alcohol, and the dosage of the acidic catalyst is more than or equal to 1ml per 1g of polyvinyl alcohol; and (3) crosslinking reaction at a crosslinking temperature of 50-53 ℃.
As can be seen from Table 4, the product performance is greatly affected by the raw material ratio and the reaction temperature, the water absorption of only examples 1, 4, 6, 9, 22 and 23 can reach more than 9.0 times, and the product is spongy, soft and good in rebound resilience. Therefore, the preferred embodiment of the present invention is that the polyvinyl alcohol is polyvinyl alcohol 1788, and the weight ratio of the potato starch to the corn starch is 4: 1; the cross-linking agent is formaldehyde or paraformaldehyde; the dosage of the water is 13-15 ml per 1g of polyvinyl alcohol, the dosage of the cross-linking agent is 1.2-1.5 ml per 1g of polyvinyl alcohol, the dosage of the pore-forming agent is 0.5g per 1g of polyvinyl alcohol, and the dosage of the acid catalyst is 1-1.2 ml per 1g of polyvinyl alcohol; the preferable selection of the polyvinyl alcohol dissolution temperature is 97-110 ℃, the preferable selection of the pore-forming agent addition temperature is 67 ℃, the preferable selection of the crosslinking agent addition temperature is 50 ℃, the preferable selection of the acid catalyst addition temperature is 50 ℃ and the preferable selection of the heat preservation temperature is 50 ℃.
Although the water absorption effect of examples 6, 9 and 22 is better than that of example 1, the pore diameter range of example 1 is smaller, therefore, the cross-linking agent dosage of comparative examples 1 and 6 is optimally 1.2ml per 1g of polyvinyl alcohol, the cross-linking agent dosage of comparative examples 1 and 9 is optimally formaldehyde, and the acid catalyst dosage of comparative examples 1 and 22 is optimally 1ml per 1g of polyvinyl alcohol in terms of the comprehensive pore diameter range with the water absorption rate being more than 10.5 times and the uniform pore diameter.
In addition, the amount of water used in comparative examples 1 and 6 is most preferably 13ml per 1g of polyvinyl alcohol, and the dissolution temperature of the polyvinyl alcohol in comparative examples 1 and 23 is most preferably 97 ℃.
Nine, size
The diameter and the limit deviation of the cervical dilating rod of example 58 meet the requirements of the following table.
TABLE 5
The data result of 72.48 + -5.46 mm of the total length of the uterus and 30.35 + -5.48 mm of the cervix is measured by adopting a multicenter 13 provinces and 1704 large samples of 20-40 years old women. The uterus dilatation is mainly characterized in that the cervical internal orifice is dilated, the shortest length of the effective use part of the cervical dilatation stick body is larger than the maximum length of the cervix, and the length of the cervical dilatation stick body of the embodiment 58 is more than or equal to 50mm by adding the length of the clamping section.
The above is only a preferred embodiment of the present invention, and it should be noted that the above preferred embodiment should not be considered as limiting the present invention, and the protection scope of the present invention should be subject to the scope defined by the claims. It will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the spirit and scope of the invention, and these modifications and adaptations should be considered within the scope of the invention.
Claims (10)
1. A method for preparing a polyvinyl acetal foam material, comprising:
(1) preparation of polyvinyl acetal cellular foam: mixing the raw materials, and reacting to obtain the polyvinyl acetal porous foam; the raw materials consist of polyvinyl alcohol, water, a cross-linking agent, a pore-forming agent and an acid catalyst; the pore-forming agent is potato starch and corn starch, and the weight ratio of the potato starch to the corn starch is 3.5-4.5: 1; the cross-linking agent is formaldehyde or paraformaldehyde; the dosage of the water is 10-15 ml per 1g of polyvinyl alcohol, the dosage of the cross-linking agent is 1.0-1.5 ml per 1g of polyvinyl alcohol, the dosage of the pore-forming agent is 0.45-0.55 g per 1g of polyvinyl alcohol, and the dosage of the acidic catalyst is more than or equal to 1ml per 1g of polyvinyl alcohol;
(2) cutting;
(3) drying;
(4) and (4) compression molding.
2. The method according to claim 1, wherein the crosslinking agent is formaldehyde.
3. The method according to claim 1, wherein the reaction is a crosslinking reaction at a crosslinking temperature of 50 to 53 ℃.
4. The method according to claim 1, wherein the process for preparing the cellular foam of polyvinyl acetal comprises:
A. mixing polyvinyl alcohol and water, stirring, and heating at 80-110 ℃ until the polyvinyl alcohol is completely dissolved; the water consumption is 10-15 ml per 1g of polyvinyl alcohol;
B. controlling the temperature to be 53-78 ℃, adding the pore-forming agent, stirring, and reacting for 5-20 min; the pore-forming agent is potato starch and corn starch, and the weight ratio of the potato starch to the corn starch is 3.5-4.5: 1; the cross-linking agent is formaldehyde or paraformaldehyde; the amount of the pore-forming agent is 0.45-0.55 g per 1g of polyvinyl alcohol;
C. controlling the temperature to be 50-53 ℃, adding the cross-linking agent, stirring, and reacting for 5-20 min; the cross-linking agent is formaldehyde or paraformaldehyde; the dosage of the cross-linking agent is 1.0-1.5 ml per 1g of polyvinyl alcohol;
D. controlling the temperature to be 50-53 ℃, adding the acidic catalyst, stirring, and reacting for 10-25 min; the dosage of the acidic catalyst is more than or equal to 1ml per 1g of polyvinyl alcohol;
E. preserving the heat for 6 to 12 hours at the temperature of between 50 and 53 ℃;
F. and (3) post-treating the polyvinyl acetal porous foam until the pH value is 6-7, and removing the residual formaldehyde.
5. The preparation method according to claim 1, wherein the step (2) specifically comprises: controlling the water content of the polyvinyl acetal porous foam to be 40-60 wt%, and freezing and cutting.
6. The preparation method according to claim 5, wherein the step (2) specifically comprises: centrifuging the polyvinyl acetal porous foam, adding water until the water content of the polyvinyl acetal porous foam is 40-60 wt%, and freezing and cutting.
7. The method for preparing according to claim 1, wherein the drying process is in particular forced air drying or pulsating vacuum sterilization drying.
8. The preparation method according to claim 1, wherein the compression molding process is specifically: and (4) compression molding by adopting a hydraulic press.
9. A polyvinyl acetal foam material produced by the production method according to any one of claims 1 to 8.
10. A cervical dilation apparatus, comprising: the cervical dilation rod body; the cervical dilating rod body is the polyvinyl acetal foam material prepared by the preparation method of any one of claims 1 to 8.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112891997A (en) * | 2021-01-29 | 2021-06-04 | 中国科学院长春应用化学研究所 | Emulsion separation material and preparation method thereof |
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| CN112891997A (en) * | 2021-01-29 | 2021-06-04 | 中国科学院长春应用化学研究所 | Emulsion separation material and preparation method thereof |
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