阅读说明：本技术 一种高性能金刚线分散剂、制备方法及其混合装置 (High-performance diamond wire dispersing agent, preparation method and mixing device thereof ) 是由 秦敬龙 于 2021-07-07 设计创作，主要内容包括：本发明提供一种高性能金刚线分散剂,由以下重量份原料组成：甲基丙烯酸、丙烯酰胺、引发剂、水、高级醇和油酸酰,所述甲基丙烯酸10-70份、丙烯酰胺10-50份、引发剂5-20份、水100份、高级醇3-8份、油酸酰2-5份,优选的,由以下重量份原料组成：甲基丙烯酸50份、丙烯酰胺10份、引发剂6份、水27份、高级醇4份、油酸酰3份。本发明提供的一种高性能金刚线分散剂,在分散剂的内部使用于丙稀酰胺具有良好的协同作用,所得的分散剂具有良好的分散性能及储存稳定,使用引发剂有利于增加产生的自由基数量,增加反应活性中心数量,提高聚合反应速度,同时有利于实现对分散剂分子量的有效控制,在分散剂的内部设置高级醇可改善润滑性和热稳定性。(The invention provides a high-performance diamond wire dispersing agent which is prepared from the following raw materials in parts by weight: the acrylic acid-containing emulsion comprises, by weight, 10-70 parts of methacrylic acid, 10-50 parts of acrylamide, 5-20 parts of an initiator, 100 parts of water, 3-8 parts of a higher alcohol and 2-5 parts of oleic acid acyl, and preferably consists of the following raw materials in parts by weight: 50 parts of methacrylic acid, 10 parts of acrylamide, 6 parts of an initiator, 27 parts of water, 4 parts of higher alcohol and 3 parts of oleic acid acyl. According to the high-performance diamond wire dispersing agent provided by the invention, acrylamide is used in the dispersing agent to have a good synergistic effect, the obtained dispersing agent has good dispersing performance and storage stability, the initiator is used to increase the number of generated free radicals, increase the number of reactive centers, improve the polymerization reaction speed, and simultaneously facilitate the realization of effective control on the molecular weight of the dispersing agent, and the higher alcohol is arranged in the dispersing agent to improve the lubricating property and the thermal stability.)

1. A high-performance diamond wire dispersing agent is characterized by comprising the following raw materials in parts by weight:

the emulsion comprises, by weight, 10-70 parts of methacrylic acid, 10-50 parts of acrylamide, 5-20 parts of an initiator, 100 parts of water, 3-8 parts of a higher alcohol and 2-5 parts of oleic acid acyl.

2. The high-performance diamond wire dispersing agent according to claim 1, which is characterized by comprising the following raw materials in parts by weight:

50 parts of methacrylic acid, 10 parts of acrylamide, 6 parts of an initiator, 27 parts of water, 4 parts of higher alcohol and 3 parts of oleic acid acyl.

3. A preparation method of a high-performance diamond wire dispersing agent is characterized by comprising the following steps:

s1, heating and melting the methacrylic acid in a melting device according to the proportion;

s2, placing acrylamide and water in a stirring device for mixing in the process of melting methacrylic acid;

s3, pouring the mixed solution of acrylamide and water into the melted methacrylic acid for mixing after the methacrylic acid is melted;

s4, mixing the initiator and water according to a component proportion;

s5, adding water into the reaction container, heating to 80-90 ℃ while stirring, adding the mixed solution of the initiator and the water below the temperature in the S3, and continuously keeping the temperature at 80-90 ℃;

s6, dropwise adding the mixed solution of acrylamide and water and the rest of mixed solution of the initiator and water for 3-5 hours;

s7, finally, adding the higher alcohol and the oleic acid acyl into the dropwise added solution in proportion, and mixing at high temperature.

4. The preparation method of the high-performance diamond wire dispersing agent according to claim 1, wherein the initiator can be potassium persulfate, sodium persulfate or ammonium persulfate.

5. The utility model provides a mixing arrangement of high performance buddha's warrior attendant line dispersant, its characterized in that, includes the base, the surface of base is provided with the processing case, the inside of processing case is provided with rotating device, rotating device includes first motor, shaft coupling fixedly connected with rotation case is passed through to the one end of first motor output shaft.

6. The mixing device of the high-performance diamond wire dispersing agent according to claim 5, wherein a stirring device is arranged inside the processing box, the stirring device comprises a second motor, one end of an output shaft of the second motor is fixedly connected with a rotating rod through a coupler, and a stirring rod is arranged on the surface of the rotating rod.

7. The mixing device of high-performance diamond wire dispersing agent according to claim 5, wherein a first blanking assembly is arranged at the top of the processing box, the first blanking assembly comprises a storage box, a batching container is arranged below the storage box, and connecting pipes are arranged at the top and the bottom of the batching container.

8. The high-performance diamond wire dispersing agent according to claim 7, wherein a pushing assembly is arranged inside the batching container, the pushing assembly comprises a push rod, and a pushing ring is fixedly connected to the bottom end of the push rod.

9. The mixing device of the high-performance diamond wire dispersing agent according to claim 5, wherein a second blanking component is arranged on one side of the top of the surface of the processing box, the second blanking component comprises a mounting frame, a mixing box is arranged inside the mounting frame, a quantitative container is arranged below the mixing box, and communicating pipes are arranged at the top end and the bottom of the quantitative container.

10. The mixing device of the high-performance diamond wire dispersing agent according to claim 9, wherein a mixing mechanism is arranged inside the mixing box, the mixing mechanism comprises a motor, and one end of an output shaft of the motor is fixedly connected with a mixing rod through a coupler.

Technical Field

The invention relates to the field of diamond wires, in particular to a high-performance diamond wire dispersing agent, a preparation method and a mixing device thereof.

Background

Diamond wire is a short name for diamond cutting wire and is used for cutting hard and brittle materials in industry.

In the conventional diamond wire processing operation, a dispersant is required to be used for auxiliary operation, and the dispersant is a surfactant which has two opposite properties of lipophilicity and hydrophilicity in a molecule.

The existing diamond wire dispersing agent is easy to cause poor performance to products in the using process, can cause poor twisting and poor breaking force and poor dispersion of active diamond sand, and can cause the phenomenon of agglomeration in the using process.

Therefore, it is necessary to provide a high-performance diamond wire dispersing agent, a preparation method and a mixing device thereof to solve the above technical problems.

Disclosure of Invention

The invention provides a high-performance diamond wire dispersing agent, a preparation method and a mixing device thereof, and solves the problem that the existing dispersing agent can generate agglomeration in the using process.

In order to solve the technical problems, the invention provides a high-performance diamond wire dispersing agent which is prepared from the following raw materials in parts by weight:

the emulsion comprises, by weight, 10-70 parts of methacrylic acid, 10-50 parts of acrylamide, 5-20 parts of an initiator, 100 parts of water, 3-8 parts of a higher alcohol and 2-5 parts of oleic acid acyl.

Preferably, the feed additive consists of the following raw materials in parts by weight:

50 parts of methacrylic acid, 10 parts of acrylamide, 6 parts of an initiator, 27 parts of water, 4 parts of higher alcohol and 3 parts of oleic acid acyl.

A preparation method of a high-performance diamond wire dispersing agent comprises the following steps:

s1, heating and melting the methacrylic acid in a melting device according to the proportion;

s2, placing acrylamide and water in a stirring device for mixing in the process of melting methacrylic acid;

s3, pouring the mixed solution of acrylamide and water into the melted methacrylic acid for mixing after the methacrylic acid is melted;

s4, mixing the initiator and water according to a component proportion;

s5, adding water into the reaction container, heating to 80-90 ℃ while stirring, adding the mixed solution of the initiator and the water below the temperature in the S3, and continuously keeping the temperature at 80-90 ℃;

s6, dropwise adding the mixed solution of acrylamide and water and the rest of mixed solution of the initiator and water for 3-5 hours;

s7, finally, adding the higher alcohol and the oleic acid acyl into the dropwise added solution in proportion, and mixing at high temperature.

Preferably, potassium persulfate, sodium persulfate, and ammonium persulfate may be used as the initiator.

The utility model provides a mixing arrangement of high performance buddha's warrior attendant line dispersant, includes the base, the surface of base is provided with the processing case, the inside of processing case is provided with rotating device, rotating device includes first motor, shaft coupling fixedly connected with rotation case is passed through to the one end of first motor output shaft.

Preferably, the inside of processing case is provided with agitating unit, agitating unit includes the second motor, shaft coupling fixedly connected with dwang is passed through to the one end of second motor output shaft, the surface of dwang is provided with the puddler.

Preferably, the top of processing case is provided with first unloading subassembly, first unloading subassembly includes the storage case, the below of storage case is provided with the batching container, the top and the bottom of batching container all are provided with the connecting pipe.

Preferably, the inside of batching container is provided with the promotion subassembly, the promotion subassembly includes the push rod, the bottom fixedly connected with of push rod pushes away the ring.

Preferably, one side at processing case surface top is provided with second unloading subassembly, second unloading subassembly includes the mounting bracket, the inside of mounting bracket is provided with the mixing box, the below of mixing box is provided with quantitative container, quantitative container's top and bottom all are provided with communicating pipe.

Preferably, the inside of mixing box is provided with mixing mechanism, mixing mechanism includes the motor, the one end of motor output shaft passes through shaft coupling fixedly connected with mixing rod.

Compared with the related art, the high-performance diamond wire dispersing agent, the preparation method and the mixing device provided by the invention have the following beneficial effects:

the invention provides a high-performance diamond wire dispersing agent, which has good synergistic effect on acrylamide in the dispersing agent, the obtained dispersing agent has good dispersing performance and storage stability, the use of an initiator is beneficial to increasing the number of generated free radicals, increasing the number of reactive centers, improving the polymerization reaction speed, and simultaneously being beneficial to realizing effective control on the molecular weight of the dispersing agent, and the arrangement of high-grade alcohol in the dispersing agent can improve the lubricating property and thermal stability and improve the performance of the dispersing agent.

Drawings

Fig. 1 is a schematic structural diagram of a mixing device of a high-performance diamond wire dispersant according to a preferred embodiment of the present invention;

FIG. 2 is a schematic structural view of the stirring device shown in FIG. 1;

FIG. 3 is a schematic structural view of the first blanking assembly shown in FIG. 1;

FIG. 4 is a schematic structural view of the second blanking assembly shown in FIG. 1;

FIG. 5 is a schematic isometric view of the device of FIG. 1 as a whole;

FIG. 6 is a front view of the device shown in FIG. 1 in its entirety;

FIG. 7 is an enlarged view of portion A of FIG. 6;

FIG. 8 is a side view of the device shown in FIG. 1 in its entirety;

FIG. 9 is a schematic view of the odor elimination device shown in FIG. 1;

fig. 10 is a bottom view of the device shown in fig. 1 as a whole.

Reference numbers in the figures:

1. a base, a processing box 2 and a processing box,

3. a rotating device 31, a first motor 32, a rotating box,

4. a stirring device 41, a second motor 42, a rotating rod 43 and a stirring rod,

5. a first blanking component 51, a storage box 52, a batching container 53, a connecting pipe,

6. a pushing component 61, a push rod 62, a pushing ring,

7. a second blanking component 71, a mounting rack 72, a mixing box 73, a quantitative container 74, a communicating pipe,

8. a mixing mechanism 81, a motor 82, a mixing rod,

9. deodorizing device 91, drain pipe, 92, air inlet cover, 93, conveying device, 94, processing box, 95, filter member.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to fig. 1 to 10 in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. The specific embodiments described herein are merely illustrative of the invention and do not delimit the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

First embodiment

A high-performance diamond wire dispersing agent is composed of the following raw materials in parts by weight:

the emulsion comprises, by weight, 10-70 parts of methacrylic acid, 10-50 parts of acrylamide, 5-20 parts of an initiator, 100 parts of water, 3-8 parts of a higher alcohol and 2-5 parts of oleic acid acyl.

The composition is characterized by comprising the following raw materials in parts by weight:

50 parts of methacrylic acid, 10 parts of acrylamide, 6 parts of an initiator, 27 parts of water, 4 parts of higher alcohol and 3 parts of oleic acid acyl.

A preparation method of a high-performance diamond wire dispersing agent comprises the following steps:

s1, heating and melting 50 parts of methacrylic acid in a melting device according to the mixture ratio;

s2, placing 10 parts of acrylamide and 27 parts of water in a stirring device for mixing in the process of melting the methacrylic acid;

s3, pouring a mixed solution of 10 parts of acrylamide and 27 parts of water into the melted methacrylic acid for mixing after the methacrylic acid is melted;

s4, mixing 6 parts of initiator and 27 parts of water according to a weight ratio;

s5, adding water into the reaction vessel, heating to 80-90 ℃ while stirring, adding a mixed solution of 6 parts of the initiator and 27 parts of water in the part below the part in the S3, and continuously keeping the temperature at 80-90 ℃;

s6, dropwise adding the mixed solution of 10 parts of acrylamide and 27 parts of water and the rest mixed solution of the initiator and the water for 3-5 hours;

s7, finally, adding 4 parts of higher alcohol and 3 parts of oleic acid acyl into the dropwise added solution in proportion, and mixing at high temperature.

As the initiator, potassium persulfate, sodium persulfate, or ammonium persulfate can be used.

Compared with the related art, the high-performance diamond wire dispersing agent provided by the invention has the following beneficial effects:

the invention provides a high-performance diamond wire dispersing agent, which has good synergistic effect on acrylamide in the dispersing agent, the obtained dispersing agent has good dispersing performance and storage stability, the use of an initiator is beneficial to increasing the number of generated free radicals, increasing the number of reactive centers, improving the polymerization reaction speed, and simultaneously being beneficial to realizing effective control on the molecular weight of the dispersing agent, and the arrangement of high-grade alcohol in the dispersing agent can improve the lubricating property and thermal stability and improve the performance of the dispersing agent.

Second embodiment

A high-performance diamond wire dispersing agent is composed of the following raw materials in parts by weight:

the emulsion comprises, by weight, 10-70 parts of methacrylic acid, 10-50 parts of acrylamide, 5-20 parts of an initiator, 100 parts of water, 3-8 parts of a higher alcohol and 2-5 parts of oleic acid acyl.

The composition is characterized by comprising the following raw materials in parts by weight:

40 parts of methacrylic acid, 20 parts of acrylamide, 9 parts of an initiator, 24 parts of water, 3 parts of higher alcohol and 4 parts of oleic acid acyl.

A preparation method of a high-performance diamond wire dispersing agent comprises the following steps:

s1, heating and melting 40 parts of methacrylic acid in a melting device according to the mixture ratio;

s2, placing 20 parts of acrylamide and 24 parts of water in a stirring device for mixing in the process of melting the methacrylic acid;

s3, pouring the mixed solution of 20 parts of acrylamide and 24 parts of water into the melted methacrylic acid for mixing after the methacrylic acid is melted;

s4, mixing 9 parts of initiator and 24 parts of water according to a weight ratio;

s5, adding water into the reaction vessel, heating to 80-90 ℃ while stirring, adding a mixed solution of 9 parts of the initiator and 24 parts of water in the part below the part in the S3, and continuously keeping the temperature at 80-90 ℃;

s6, dropwise adding the mixed solution of 20 parts of acrylamide and 24 parts of water and the rest mixed solution of the initiator and the water, wherein the operation time is 3-5 hours;

s7, finally adding 3 parts of higher alcohol and 4 parts of oleic acid acyl into the dropwise added solution in proportion, and mixing at high temperature.

Third embodiment

A high-performance diamond wire dispersing agent is composed of the following raw materials in parts by weight:

the emulsion comprises, by weight, 10-70 parts of methacrylic acid, 10-50 parts of acrylamide, 5-20 parts of an initiator, 100 parts of water, 3-8 parts of a higher alcohol and 2-5 parts of oleic acid acyl.

The composition is characterized by comprising the following raw materials in parts by weight:

60 parts of methacrylic acid, 10 parts of acrylamide, 5 parts of an initiator, 20 parts of water, 3 parts of higher alcohol and 2 parts of oleic acid acyl.

A preparation method of a high-performance diamond wire dispersing agent comprises the following steps:

s1, heating and melting 60 parts of methacrylic acid in a melting device according to the mixture ratio;

s2, placing 10 parts of acrylamide and 20 parts of water in a stirring device for mixing in the process of melting the methacrylic acid;

s3, pouring a mixed solution of 10 parts of acrylamide and 20 parts of water into the melted methacrylic acid for mixing after the methacrylic acid is melted;

s4, mixing 5 parts of initiator and 20 parts of water according to a weight ratio;

s5, adding water into the reaction vessel, heating to 80-90 ℃ while stirring, adding a mixed solution of 5 parts of the initiator and 20 parts of water in the part below the part in the S3, and continuously keeping the temperature at 80-90 ℃;

s6, dropwise adding the mixed solution of 10 parts of acrylamide and 20 parts of water and the rest mixed solution of the initiator and the water for 3-5 hours;

s7, finally adding 3 parts of higher alcohol and 2 parts of oleic acid acyl into the dropwise added solution in proportion, and mixing at high temperature.

For the testing of the throw-off point, throw-off height and twist circle of the high performance diamond wire dispersants prepared in examples 1-3, the data of all examples were normalized based on the data of example 1 for ease of comparison.

TABLE 1

As can be seen from the above table, the high performance diamond wire dispersant prepared in example 2 has higher test results of the sharpening rate, the sharpening height and the torsion ring than those of the examples, so the process of the high performance diamond wire dispersant prepared in example 2 is the optimal choice.

Fourth embodiment

The utility model provides a mixing arrangement of high performance buddha's warrior attendant line dispersant, includes base 1, the surface of base 1 is provided with processing case 2, the inside of processing case 2 is provided with rotating device 3, rotating device 3 includes first motor 31, shaft coupling fixedly connected with rotation case 32 is passed through to the one end of first motor 31 output shaft.

First motor 31 is through the bottom threaded connection of threaded bolt with base 1, the output shaft and the shaft coupling of first motor 31 run through the bottom of base 1 inner wall and extend to the inside of processing case 2, use first motor 31 and rotate the abundant mixture of raw materials when case 32 can, the surface cover that rotates case 32 is equipped with the ring baffle, use mechanical seal between ring baffle and the rotation case 32, the effect that liquid blockked when using the ring baffle to the ejection of compact of raw materials, the inner wall fixed connection of ring baffle and processing case 2, set up the fluid-discharge tube in the one side of rotating case 32 bottom.

The inside of processing case 2 is provided with agitating unit 4, agitating unit 4 includes second motor 41, shaft coupling fixedly connected with dwang 42 is passed through to the one end of second motor 41 output shaft, the surface of dwang 42 is provided with puddler 43.

The second motor 41 is connected with the surface thread at the top of the processing box 2 through a thread bolt, the output shaft and the shaft coupling of the second motor 41 penetrate through the surface of the processing box 2 and extend to the inside of the processing box 2, the two sides of the surface of the rotating rod 42 are sequentially provided with a plurality of stirring rods 43 from top to bottom, and the rotating rod 42 and the stirring rods 43 are arranged inside the rotating box 32.

The top of processing case 2 is provided with first unloading subassembly 5, first unloading subassembly 5 includes storage case 51, the below of storage case 51 is provided with batching container 52, the top and the bottom of batching container 52 all are provided with connecting pipe 53.

The material storage box 51 is fixedly installed at the left side of the top of the surface of the processing box 2, and valves are arranged inside the connecting pipes 53 arranged at the top and the bottom of the batching container 52, so that the conveying amount of raw materials can be controlled.

The inside of batching container 52 is provided with pushing assembly 6, pushing assembly 6 includes push rod 61, the bottom fixedly connected with of push rod 61 pushes away ring 62.

One end of the push rod 61 penetrates through one side of the top of the inner wall of the ingredient container 52 and extends to the outer side of the ingredient container 52, a communicating hole is formed in the connecting position of the push rod 61 and the ingredient container 52, so that the push rod 61 can move conveniently, the push rod 61 is a folding rod, the folding rod can adapt to operation with various lengths, and the pushing ring 62 can be used for removing residual raw materials on the inner wall of the ingredient container 52.

One side at processing case 2 surface top is provided with second unloading subassembly 7, second unloading subassembly 7 includes mounting bracket 71, the inside of mounting bracket 71 is provided with mixing box 72, the below of mixing box 72 is provided with quantitative container 73, the top and the bottom of quantitative container 73 all are provided with communicating pipe 74.

The mounting bracket 71 is fixedly installed at the right side of the top of the surface of the processing box 2, and valves are provided inside the connection pipes 74 provided at the top and bottom of the quantitative container 73, so that the amount of the raw material to be transferred can be controlled.

The inside of mixing box 72 is provided with mixing mechanism 8, mixing mechanism 8 includes motor 81, the one end of motor 81 output shaft passes through shaft coupling fixedly connected with mixing rod 82.

A smell removal device 9 is arranged on one side of the processing box 2, the smell removal device 9 comprises a liquid outlet pipe 91, an air inlet cover 92 is arranged on the surface of the liquid outlet pipe 91, a conveying device 93 is arranged on one side of the air inlet cover 92, a processing box 94 is arranged on one side of the conveying device 93, and a filtering piece 95 is arranged inside the processing box 94.

The cover 92 is cylindrical to seted up the round intercommunicating pore in columniform bottom, conveyor 93 includes the pump body, and the input intercommunication at the pump body has the intake pipe, and the one end of intake pipe and the one side intercommunication of cover 92 are admitted, and the output intercommunication of the pump body has the outlet duct, and the one end of outlet duct communicates with one side of handling case 94, and it can use activated carbon to carry out getting rid of taste to filter piece 95, is provided with the blast pipe in the one side of handling case 94.

The working principle of the high-performance diamond wire dispersing agent provided by the invention is as follows:

during the use, when carrying out the mixture of raw materials, the operator at first flows the inside to batching container 52 and carries out the control of proportion through connecting pipe 53 with the raw materials that mix between, open the switch of bottom after the inside raw materials of batching container 52 are carried to appointed proportion and make the raw materials carry the inside to rotating box 32 through connecting pipe 53, start first motor 31 and drive rotating box 32 and rotate after the raw materials are carried to rotating box 32's inside, when rotating box 32 rotates, start second motor 41 and drive rotating box 32 inside dwang 42 and puddler 43 and rotate and carry out abundant stirring to the raw materials.

When the raw materials are required to be premixed and then added into the rotating box 32, the raw materials required to be premixed are firstly conveyed into the mixing box 72, after the raw materials are added into the mixing box 72, the motor 81 is started to drive the mixing rod 82 to premix the raw materials in the mixing box 72, after the raw materials in the mixing box 72 are premixed, the switch on one side of the communicating pipe 74 is opened to convey the raw materials into the quantitative container 73, after the raw materials are conveyed into the quantitative container 73 and added into the quantitative container 73 in a specified proportion, the switch below the quantitative container 73 is opened to convey the raw materials into the rotating box 32 to be continuously mixed.

After the raw materials are mixed, the raw materials are conveyed to a designated position through the liquid outlet pipe 91, the conveying device 93 is started to convey odor generated by the raw materials to the inside of the treatment box 94 through the air inlet hood 92, and after the gas enters the inside of the treatment box 94, the gas can be discharged after being treated through the filtering piece 95 inside the treatment box 94.

Compared with the related art, the high-performance diamond wire dispersing agent provided by the invention has the following beneficial effects:

the invention provides a high-performance diamond wire dispersing agent, wherein a first motor 31 arranged at the bottom of a base 1 and a rotating box 32 arranged in a processing box 2 are matched with a second motor 41, a rotating rod 42 and a stirring rod 43 for use, so that raw materials can be fully stirred, a push ring 62 arranged in a batching container 52 is matched with a push rod 61 for use, so that the residual raw materials on the inner wall of the batching container 52 can be removed, a motor 81 arranged at the top of a mixing box 72 is matched with a mixing rod 82 in the mixing box 72 for use, so that the raw materials needing to be mixed in advance can be mixed, the batching container 52 and a quantitative container 73 respectively arranged below a storage box 51 and the mixing box 72 can control the proportion of the raw materials, the influence of the later processing operation caused by the difference of the proportion of the raw materials is prevented, a deodorizing device 9 arranged at one side of the base 1 can absorb gas generated when a mixed solution is discharged, prevent that smell from spreading in the air and can influence operator's operation, can cause operator's health to appear the damage.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.