CN110560628B - Preparation method of curing agent for self-hardening furan resin - Google Patents
Preparation method of curing agent for self-hardening furan resin Download PDFInfo
- Publication number
- CN110560628B CN110560628B CN201910799943.8A CN201910799943A CN110560628B CN 110560628 B CN110560628 B CN 110560628B CN 201910799943 A CN201910799943 A CN 201910799943A CN 110560628 B CN110560628 B CN 110560628B
- Authority
- CN
- China
- Prior art keywords
- curing agent
- self
- furan resin
- sulfonic acid
- hardening furan
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
- B22C1/16—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents
- B22C1/20—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents
- B22C1/22—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents of resins or rosins
- B22C1/2233—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents of resins or rosins obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- B22C1/224—Furan polymers
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Mold Materials And Core Materials (AREA)
Abstract
The invention relates to a preparation method of a curing agent for self-hardening furan resin. The chemical components of the self-hardening furan resin curing agent comprise sulfonic acid, sulfate, phosphoric acid, a modifier and water; the preparation method of the curing agent for the self-hardening furan resin comprises the following steps: a. weighing sulfonic acid, adding the sulfonic acid into a reaction kettle, adding water through a metering tank, and starting a stirrer; b. after water is added, sucking sulfuric ester and phosphoric acid into the reaction kettle in vacuum, and stirring for 15 min; c. absorbing a modifier into the reaction kettle in vacuum, and stirring for 30min to obtain a curing agent; d. and sampling and inspecting the prepared curing agent, and metering, packaging and warehousing after the curing agent is detected to be qualified. According to the invention, organic sulfonic acid and inorganic phosphoric acid are effectively combined, sulfuric ester is added to optimize the cost, and a modifier is introduced to adjust the catalytic activity of the curing agent, so that the developed series of curing agents can meet the production requirements of steel castings and iron castings in winter to summer, and the effects of excellent product performance, low production cost and strong environmental adaptability are achieved.
Description
Technical Field
The invention relates to the field of castings, in particular to a preparation method of a curing agent for self-hardening furan resin.
Background
The common curing agents currently used for casting self-hardening furan resin in the industry can be divided into two main categories: i.e., inorganic curing agents such as phosphoric acid, sulfuric acid, and the like; organic curing agents, such as benzenesulfonic acid, toluenesulfonic acid, xylenesulfonic acid, sulfuric acid esters, and the like. The inorganic curing agent has easily obtained raw materials and low price, but the acidity of the sulfuric acid and the phosphoric acid is stronger, the hardening speed of the resin sand is not easy to control, and the strength after curing is lower. The organic curing agent is p-toluenesulfonic acid widely used at present, which is prepared by sulfonating, debenzolizing, transposition crystallizing and separating toluene under the catalysis of concentrated sulfuric acid, the production process is complex, the production cost is relatively high, and the sulfonation operation belongs to dangerous operation and has certain production safety risk.
Similarly, for furan resin, if inorganic acid is selected as a curing agent, not only is the curing speed not easy to control and the strength low, but also more importantly, the phosphorus content is too high, and the casting surface has cold crack defects, and after sand molds and cores using phosphoric acid as the curing agent are poured, phosphoric acid cannot be decomposed and damaged under the thermal action of molten metal, and generated phosphate is deposited on the surface of sand particles and is difficult to remove through regeneration, so that the strength of the regenerated sand is greatly reduced during recycling, and the expansion of casting molds is increased, so that the sand inclusion tendency is increased. When the sulfuric acid ester and the sulfonic acid curing agent with over-high sulfur content are used for molding production, the hot cracking defect tendency of the surface of the steel casting is increased, and the quality of the casting is seriously influenced.
Disclosure of Invention
The invention provides a preparation method of a curing agent for self-hardening furan resin, aiming at solving the defects in the prior art. According to the invention, organic sulfonic acid and inorganic phosphoric acid are effectively combined, sulfuric ester is added to optimize the cost, and a modifier is introduced to adjust the catalytic activity of the curing agent, so that the developed series of curing agents can meet the production requirements of steel castings and iron castings in winter to summer, and the effects of excellent product performance, low production cost and strong environmental adaptability are achieved.
In order to solve the above disadvantages, the invention adopts the technical scheme that:
a preparation method of a self-hardening furan resin curing agent comprises the following chemical components of sulfonic acid, sulfate and phosphoric acid.
Further, the mass percent of the sulfonic acid is 21-48%; the mass percentage of the sulfate is 17-49%; the mass percentage of the phosphoric acid is 8-21%.
Further, the sulfonic acid is one or a combination of several of toluenesulfonic acid, xylene sulfonic acid, phenol sulfonic acid and sulfamic acid.
Further, the sulfate is one or a combination of several of dimethyl sulfate, diethyl sulfate and ethyl hydrogen sulfate.
Further, the curing agent for the self-hardening furan resin also comprises water and a modifier.
Further, the water accounts for 12-52% by mass; the mass percent of the modifier is 2-8%.
Further, the modifier is one or a combination of more of 2-methylimidazole, dicyandiamide, acethydrazide and vinyl triamine.
A preparation method of a curing agent for self-hardening furan resin comprises the following steps:
a. weighing sulfonic acid, adding the sulfonic acid into a reaction kettle, adding water through a metering tank, and starting a stirrer;
b. after water is added, sucking sulfuric ester and phosphoric acid into the reaction kettle in vacuum, and stirring for 15 min;
c. absorbing a modifier into the reaction kettle in vacuum, and stirring for 30min to obtain a curing agent;
d. and sampling and inspecting the prepared curing agent, and metering, packaging and warehousing after the curing agent is detected to be qualified.
The self-hardening furan resin sand is prepared by adopting the curing agent for the self-hardening furan resin.
A method for preparing the self-hardening furan resin sand, wherein the sand temperature in the method is-5-40 ℃; the curing agent for the self-hardening furan resin accounts for 20-70% of the addition amount of the resin.
The invention has the beneficial effects that:
the curing agent for casting the self-hardening furan resin sand effectively combines organic sulfonic acid with inorganic phosphoric acid, sulfuric ester is added to optimize the cost, a modifier is introduced to adjust the catalytic activity of the curing agent, and the developed series of curing agents can meet the production requirements of steel castings and iron castings from winter to summer. It has the following characteristics:
(1) the organic acid has larger relative molecular weight, and is beneficial to improving the strength of the molding sand when participating in the crosslinking and curing of the furan resin; the inorganic acid has high catalytic activity, can accelerate the solidification speed of the molding sand, shorten the stripping time of the sand mold (core) and improve the molding (core making) efficiency; the invention effectively combines organic acid and inorganic acid;
(2) the process curing agent can meet the requirements of steel castings on the heat strength of sand molds and can control the cost of curing agent products by adjusting the components of sulfonic acid, phosphoric acid and sulfate;
(3) the process curing agent can meet the molding production of the self-hardening furan resin sand at the sand temperature of-10-40 ℃, the usable time can be adjusted within the range of 1-16 min, the demolding time of the sand mold can be controlled within the range of 10 times of the usable time of the molding sand, the field operation is convenient, and the production efficiency is high;
(4) after the modifier is introduced in the process to modify the curing agent product, the furan resin sand is molded and produced, the sand mold stripping efficiency is improved by 30 percent, and the working efficiency is improved.
Drawings
None.
Detailed Description
In order that the invention may be more fully understood, reference will now be made to the accompanying examples. The preferred embodiments of the present invention are given in the examples. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
The specific implementation mode is as follows:
example 1:
a. weighing 21% of sulfonic acid, adding the sulfonic acid into a reaction kettle, adding 52% of water into the reaction kettle through a metering tank, and starting a stirrer;
b. after water is added, 17 percent of sulfuric ester and 8 percent of phosphoric acid are sucked into the reaction kettle in vacuum, and stirred for 15 min;
c. 2 percent of modifier is sucked into the reaction kettle in vacuum, and the stirring is carried out for 30 min;
d. sampling, inspecting, measuring, packaging and warehousing after the detection is qualified.
The curing agent product synthesized by the method belongs to a very slow curing agent, is suitable for self-hardening furan resin sand molding and core making production under the condition that the sand temperature is 35-40 ℃ in the midsummer, and the addition amount of the curing agent is recommended to be 20-70% of the weight of the resin.
Example 2:
a. weighing 28% of sulfonic acid, adding into a reaction kettle, adding 35% of water through a metering tank, and starting a stirrer;
b. after water is added, 17 percent of sulfuric ester and 16 percent of phosphoric acid are sucked into the reaction kettle in vacuum, and stirred for 15 min;
c. 4 percent of modifier is sucked into the reaction kettle in vacuum and stirred for 30 min;
d. sampling, inspecting, measuring, packaging and warehousing after the detection is qualified.
The curing agent product synthesized by the method belongs to a slow curing agent, is suitable for self-hardening furan resin sand molding and core manufacturing production at the sand temperature of 25-35 ℃, and the addition amount of the curing agent is recommended to be 20-70% of the weight of the resin.
Example 3:
a. weighing 28% of sulfonic acid, adding into a reaction kettle, adding 30% of water through a metering tank, and starting a stirrer;
b. after water is added, 26 percent of sulfuric ester and 8 percent of phosphoric acid are sucked into the reaction kettle in vacuum, and stirred for 15 min;
c. absorbing 8% of modifier into the reaction kettle in vacuum, and stirring for 30 min;
d. sampling, inspecting, measuring, packaging and warehousing after the detection is qualified.
The curing agent product synthesized by the method belongs to a medium-speed curing agent, is suitable for self-hardening furan resin sand molding and core making production at the sand temperature of 10-25 ℃, and the addition amount of the curing agent is recommended to be 20-70% of the weight of the resin.
Example 4:
a. weighing 17% of sulfonic acid, adding into a reaction kettle, adding 24% of water through a metering tank, and starting a stirrer;
b. after water is added, 49 percent of sulfuric ester and 8 percent of phosphoric acid are sucked into the reaction kettle in vacuum, and stirred for 15 min;
c. 2 percent of modifier is sucked into the reaction kettle in vacuum, and the stirring is carried out for 30 min;
d. sampling, inspecting, measuring, packaging and warehousing after the detection is qualified.
The curing agent product synthesized by the method belongs to a quick curing agent, is suitable for self-hardening furan resin sand molding and core making production at the sand temperature of 0-10 ℃, and the addition amount of the curing agent is recommended to be 20-70% of the weight of the resin.
Example 5:
a. weighing 48% of sulfonic acid, adding into a reaction kettle, adding 12% of water through a metering tank, and starting a stirrer;
b. after the water is added, sucking 17% of sulfuric ester and 21% of phosphoric acid into the reaction kettle in vacuum, and stirring for 15 min;
c. 2 percent of modifier is sucked into the reaction kettle in vacuum, and the stirring is carried out for 30 min;
d. sampling, inspecting, measuring, packaging and warehousing after the detection is qualified.
The curing agent product synthesized by the method belongs to a very fast curing agent, is suitable for molding and core-making production of self-hardening furan resin sand under the severe cold condition of sand temperature of-10-0 ℃, and the addition amount of the curing agent is recommended to be 20-70% of the weight of the resin.
The above table is a guidance suggestion, and can be specifically adjusted according to the conditions of casting plant product structure, sand quality and the like.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (5)
1. The preparation method of the self-hardening furan resin curing agent is characterized in that the chemical components of the self-hardening furan resin curing agent comprise sulfonic acid, sulfate, phosphoric acid, water and a modifier;
the sulfate is one or a combination of more of dimethyl sulfate, diethyl sulfate and ethyl hydrogen sulfate;
the modifier is one or a combination of more of 2-methylimidazole, dicyandiamide, acethydrazide and vinyl triamine;
the preparation method of the curing agent for the self-hardening furan resin comprises the following steps:
a. weighing sulfonic acid, adding the sulfonic acid into a reaction kettle, adding water through a metering tank, and starting a stirrer;
b. after water is added, sucking sulfuric ester and phosphoric acid into the reaction kettle in vacuum, and stirring for 15 min;
c. absorbing a modifier into the reaction kettle in vacuum, and stirring for 30min to obtain a curing agent;
d. and sampling and inspecting the prepared curing agent, and metering, packaging and warehousing after the curing agent is detected to be qualified.
2. The method for preparing the self-hardening furan resin curing agent of claim 1, wherein the sulfonic acid is 21 to 48% by mass; the mass percentage of the sulfate is 17-49%; the mass percentage of the phosphoric acid is 8-21%; the mass percentage of the water is 12-52%; the mass percent of the modifier is 2-8%.
3. The method for preparing the curing agent for self-hardening furan resin of claim 2, wherein the sulfonic acid is one or a combination of toluene sulfonic acid, xylene sulfonic acid, phenol sulfonic acid and sulfamic acid.
4. A self-hardening furan resin sand, characterized in that, the self-hardening furan resin sand is prepared by the method of any one of claims 1 to 3 for preparing the curing agent for self-hardening furan resin.
5. A process for preparing the self-hardening furan resin sand as claimed in claim 4, wherein the sand temperature in the process is-5 to 40 ℃; the curing agent for the self-hardening furan resin accounts for 20-70% of the addition amount of the resin.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910799943.8A CN110560628B (en) | 2019-08-30 | 2019-08-30 | Preparation method of curing agent for self-hardening furan resin |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910799943.8A CN110560628B (en) | 2019-08-30 | 2019-08-30 | Preparation method of curing agent for self-hardening furan resin |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110560628A CN110560628A (en) | 2019-12-13 |
| CN110560628B true CN110560628B (en) | 2021-08-31 |
Family
ID=68776475
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910799943.8A Active CN110560628B (en) | 2019-08-30 | 2019-08-30 | Preparation method of curing agent for self-hardening furan resin |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110560628B (en) |
Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101722272A (en) * | 2009-11-19 | 2010-06-09 | 东方电气集团东方汽轮机有限公司 | Curing agent of self-hardening furan resin sand and preparation method thereof |
| CN102977824A (en) * | 2011-09-06 | 2013-03-20 | 甘肃郝氏炭纤维有限公司 | High temperature binder used for binding carbon material, and preparation method and application method thereof |
| CN103086642A (en) * | 2012-04-25 | 2013-05-08 | 北京仁创科技集团有限公司 | Oxygen-releasing quick curing patching material as well as preparation method and application of material |
| CN104588569A (en) * | 2014-12-29 | 2015-05-06 | 北京仁创科技集团有限公司 | Fast-curing type high-temperature resistant binder and pre-coated sand thereof |
| CN106269025A (en) * | 2016-08-18 | 2017-01-04 | 江阴联华铸造有限公司 | A kind of train parts furan resin for casting overlay film core sand and preparation method thereof |
| CN106391993A (en) * | 2016-09-07 | 2017-02-15 | 济南大学 | Preparation method of rapid formation coated sand for 3DP printing |
| CN106881445A (en) * | 2017-02-08 | 2017-06-23 | 宁夏共享化工有限公司 | A kind of furan resin casting is with applying mechanically curing agent and preparation method thereof |
| CN107282868A (en) * | 2017-06-22 | 2017-10-24 | 安徽银力铸造有限公司 | A kind of preparation method cast with antistatic furan resin-sand |
| CN108543908A (en) * | 2018-04-20 | 2018-09-18 | 苏州兴业材料科技股份有限公司 | A kind of 3D sand molds printing furane resins curing agent and preparation method thereof |
| CN109108213A (en) * | 2017-06-23 | 2019-01-01 | 宁夏共享化工有限公司 | Curing agent is used in a kind of casting |
| CN109175221A (en) * | 2018-10-16 | 2019-01-11 | 阜新力达钢铁铸造有限公司 | A kind of casting self-hardening furan resin curing agent and preparation method thereof |
| CN109967690A (en) * | 2019-03-27 | 2019-07-05 | 烟台通鼎舟汽车零部件有限公司 | A kind of thin-walled aluminium alloy castings gravitational casting precoated sand and its application method |
| CN110177634A (en) * | 2016-12-23 | 2019-08-27 | Ask化学品股份有限公司 | The adhesive based on benzyl oxide type phenolic resin comprising free phenol and free hydroxyl group benzylalcohol |
-
2019
- 2019-08-30 CN CN201910799943.8A patent/CN110560628B/en active Active
Patent Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101722272A (en) * | 2009-11-19 | 2010-06-09 | 东方电气集团东方汽轮机有限公司 | Curing agent of self-hardening furan resin sand and preparation method thereof |
| CN102977824A (en) * | 2011-09-06 | 2013-03-20 | 甘肃郝氏炭纤维有限公司 | High temperature binder used for binding carbon material, and preparation method and application method thereof |
| CN103086642A (en) * | 2012-04-25 | 2013-05-08 | 北京仁创科技集团有限公司 | Oxygen-releasing quick curing patching material as well as preparation method and application of material |
| CN104588569A (en) * | 2014-12-29 | 2015-05-06 | 北京仁创科技集团有限公司 | Fast-curing type high-temperature resistant binder and pre-coated sand thereof |
| CN106269025A (en) * | 2016-08-18 | 2017-01-04 | 江阴联华铸造有限公司 | A kind of train parts furan resin for casting overlay film core sand and preparation method thereof |
| CN106391993A (en) * | 2016-09-07 | 2017-02-15 | 济南大学 | Preparation method of rapid formation coated sand for 3DP printing |
| CN110177634A (en) * | 2016-12-23 | 2019-08-27 | Ask化学品股份有限公司 | The adhesive based on benzyl oxide type phenolic resin comprising free phenol and free hydroxyl group benzylalcohol |
| CN106881445A (en) * | 2017-02-08 | 2017-06-23 | 宁夏共享化工有限公司 | A kind of furan resin casting is with applying mechanically curing agent and preparation method thereof |
| CN107282868A (en) * | 2017-06-22 | 2017-10-24 | 安徽银力铸造有限公司 | A kind of preparation method cast with antistatic furan resin-sand |
| CN109108213A (en) * | 2017-06-23 | 2019-01-01 | 宁夏共享化工有限公司 | Curing agent is used in a kind of casting |
| CN108543908A (en) * | 2018-04-20 | 2018-09-18 | 苏州兴业材料科技股份有限公司 | A kind of 3D sand molds printing furane resins curing agent and preparation method thereof |
| CN109175221A (en) * | 2018-10-16 | 2019-01-11 | 阜新力达钢铁铸造有限公司 | A kind of casting self-hardening furan resin curing agent and preparation method thereof |
| CN109967690A (en) * | 2019-03-27 | 2019-07-05 | 烟台通鼎舟汽车零部件有限公司 | A kind of thin-walled aluminium alloy castings gravitational casting precoated sand and its application method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110560628A (en) | 2019-12-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106493286B (en) | A kind of low sulfur curing agent for furan resin casting | |
| CA2581167A1 (en) | Binder composition comprising condensed tannin and furfuryl alcohol and its uses | |
| CN101569921A (en) | Casting technique for manufacturing mold core by using resin sand | |
| CN101199982B (en) | Low sulfur curing agent for furan resin casting | |
| CN103302233B (en) | A kind of thermmohardening casting binder and preparation method thereof and application | |
| CN101554644B (en) | Lost foam casting process suitable for aluminum alloy materials | |
| CN103586400A (en) | Preparation process of furan resin sand | |
| CN102836948A (en) | Regenerated coated sand and preparation method thereof | |
| CN102513500A (en) | Curing agent for Furane self-hardening resin, preparation method thereof and Furane self-hardening resin sand | |
| CN110560628B (en) | Preparation method of curing agent for self-hardening furan resin | |
| CN109108213A (en) | Curing agent is used in a kind of casting | |
| CN105108045A (en) | Chopped carbon fiber containing and reinforced type modified furan resin sand for steel casting and preparation method of resin sand | |
| CN107096871A (en) | Accelerate precoated sand of cast member shaping speed and preparation method thereof | |
| CN110860646A (en) | Foundry sand composition and casting method | |
| CN109175221B (en) | Curing agent for casting self-hardening furan resin and preparation method thereof | |
| CN109014018A (en) | A kind of inorganic adhesive and its preparation, application method | |
| CN102861866A (en) | Curing agent for furan resin self-hardening sand for casting and preparation method thereof | |
| CN111718175B (en) | CO (carbon monoxide)2Hardened inorganic binder and method for producing same | |
| Ghosh | Modern furan for modern castings | |
| Banganayi et al. | Optimisation of an environmentally friendly foundry inorganic binder core making process for the replacement of an organic binder | |
| CN102898985B (en) | Preparation method for furan nitrogen-free environment protection casting resin adhesive | |
| CN105414455A (en) | High-thermal-stability modified alkaline phenolic resin self-hardening sand for pump valve casting and preparation method of high-thermal-stability modified alkaline phenolic resin self-hardening sand | |
| CN103317083B (en) | A kind of method improving amine method cold core box core release property | |
| CN110039004A (en) | A kind of production method of high intensity railway steel-casting | |
| CN103521709B (en) | A kind of CO 2air hardening is from hard coupling Hardening Sodium Silicate sand core core-making method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20230428 Address after: 261313 50 meters east of Jinjing Avenue, Binhai (Xiaying) Economic Development Zone, Changyi City, Weifang City, Shandong Province Patentee after: Shared New Materials (Shandong) Co.,Ltd. Address before: 750021 No.66, Wenchang South Street, Xixia District, Yinchuan City, Ningxia Hui Autonomous Region Patentee before: KOCEL CHEMICALS Co.,Ltd. |
|
| TR01 | Transfer of patent right |