CN116574553A

CN116574553A - Wet lubricant for conveyor belt and preparation method and application thereof

Info

Publication number: CN116574553A
Application number: CN202310550365.0A
Authority: CN
Inventors: 李洪阳; 徐文澜
Original assignee: Wuhan Ponkong Sci & Technology Corp
Current assignee: Wuhan Ponkong Sci & Technology Corp
Priority date: 2023-05-16
Filing date: 2023-05-16
Publication date: 2023-08-11
Anticipated expiration: 2043-05-16
Also published as: CN116574553B

Abstract

The invention discloses a wet lubricant for a conveyor belt, which is prepared from the following raw materials: 1 to 10 percent of polyethylene glycol, 1 to 5 percent of nonionic surfactant, 0.1 to 10 percent of complexing scale inhibitor, 0.1 to 2 percent of bacteriostat and the balance of water; wherein the polyethylene glycol consists of PEG2000, PEG20000 and PEO 22000; the nonionic surfactant is fatty alcohol alkylene oxide nonionic surfactant, the complexing scale inhibitor is tetra sodium ethylenediamine tetraacetate and hydroxyethylidene diphosphonic acid, and the bacteriostatic agent is isothiazolinone; the invention creatively compounds polyethylene glycol and fatty alcohol alkylene oxide for use, further adds the complex scale inhibitor, and applies the complex scale inhibitor between a conveyor belt and a container in the form of a wet lubricant, thereby having the characteristics of good lubrication effect and low foamability, and simultaneously the lubricant can not corrode production equipment during use, and has higher hard water resistance, excellent antibacterial capability and good comprehensive performance.

Description

Wet lubricant for conveyor belt and preparation method and application thereof

Technical Field

The invention relates to the technical field of lubricants, in particular to a wet lubricant for a conveyer belt and a preparation method and application thereof.

Background

In the finished product packaging operation after filling of PET containers, tetra Pak, the containers are generally moved at very high speeds by a conveyor system, the conveyance being effected by movement of a conveyor belt flight, the speed of the conveyor belt evolving with efficiency requirements from 1 ten thousand bottles/hour to 7-8 ten thousand bottles/hour at present. The use of conveyor belts can cause constant friction in a number of ways, such as inter-collisions between conveyor belts and belts, between conveyor belts and containers, between assemblies of conveyor chains and gears, and between containers during transport. The friction must be reduced by applying Tu Runhua doses. Conveyor lubricants require that the optimum value of friction between the packaging container and the conveyor surface be dataized, expressed in terms of coefficient of friction, slip force, slip value, frictional resistance or the like. The purpose of the lubricant composition synthesis and dispensing in the prior art patents is to create the lowest possible coefficient of friction between the packaging container and the conveyor belt surface. In practice, this does not facilitate efficient transmission. During the actual execution of the conveyor belt lubrication program, the lowest possible coefficient of friction between the conveyed container and the conveyor belt surface is not necessarily advantageous for transport. The application of lubricant compositions between the container and the conveyor belt surface with too high or too low a coefficient of friction can lead to reduced system efficiency up to or including complete inability to transport the packaging container. In packaging containers having a height to width ratio much greater than 1, such as beverage bottles, the lack of adequate lubrication and unacceptably low coefficient of friction may result in excessive bottle tipping or tipping, difficulty in properly accessing the packaging section, and impact production efficiency. It is preferable to maintain the friction coefficient within a normal range. The friction coefficient of the lubricant is only about 0.25 at 1 ten thousand bottles/hour, while the friction coefficient of the lubricant is about 0.05-0.1 at 7-8 ten thousand bottles/hour. To meet this demand, new technology for lubricants is increasingly being used. Conveyor belt lubricants are continually being developed in an effort to meet the growing demands of the industry.

Compatibility of the lubricant composition with the pt bottle is important. However, little prior art has been able to determine PET bottle compatibility based entirely on bottle breakage (bottle failure). It is important for PET bottle compatibility that beverage bottles filled with soft drinks and exposed to conveyor lubricant solutions do not show breakage when stored. Rupture means that the filled bottle breaks or leaks and the contents flow out of the bottle. An important measure of PET compatibility of lubricant formulations is the relative failure rate of the bottles exposed to the lubricant. In the prior art, there is no positive conclusion regarding the correlation of the appearance of a bottle with the breakage rate of the bottle. Among all beverages, carbonated beverage bottles are most prone to stress cracking, with the highest requirement for compatibility of the lubricant composition with the pt bottle.

In particular, conveyor belt lubricants fall into two modes, wet lubricants and dry lubricants. The so-called wet lubricant is usually provided in the form of a concentrate and is subsequently diluted with water at the time of use to form an aqueous diluted lubricant solution (dilution ratio of 1:50 to 1:1000), and a large amount of the diluted lubricant aqueous solution is sent to a nozzle using a proportional dilution pump and sprayed onto the link plate through the nozzle. The dry lubricant is a lubricant stock solution sent to a nozzle through a pumping device and sprayed onto a chain plate through the nozzle to provide lubrication. These lubricant compositions can reduce damage to containers or labels from high speed conveyor belt operation.

Because wet lubricants require large amounts of water, there is inevitably a liquid spray around the conveyor belt environment, resulting in excessive wetting of the environment in the vicinity of the conveyor belt. The moist environment may promote the growth of microorganisms, thereby increasing the risk of microbial contamination on or near the conveyor line. And accumulated water caused by excessive lubricant solution on the floor is easy to slip down, so that potential safety hazard is caused. Variations in the water source used for on-site lubricant dilution can result in variations in the chemical composition of the lubricant, such as large amounts of multivalent cations in hard water, and thus can also negatively impact the efficacy of the lubricant. Because the water quality is different, the use effect is different in different places, and even the use requirement can not be met completely. At the same time, variations in water supply pressure may also cause variations in the actual dilution ratio, which all lead to problems with lubricant efficacy. The amount of water discharged to the sewage treatment system is large; during the use process. As such, diluting the lubricant with large amounts of water results in wasted resources, is environmentally unfriendly and expensive. The water used to dilute the concentrated lubricant solution may in turn cause stress cracking of the (pt) bottle. In addition to the high cost, environmental impact, the risks associated with wet surfaces, and the risk of container stress cracking, wet lubricants have many adverse effects in this regard of use.

While better dry lubricants, which have no adverse effect on the conveyor belt environment, are cost effective in composition and compatible with PET materials. Dry lubricants appear to meet some growing requirements. However, in practice, wet lubricants have the incomparable advantage of dry lubricants, and the continuous flow of the lubricant diluent results in a good hygiene of the conveyor belt and the drip tray. The lubrication requirements for each portion of the belt are not exactly the same, as in the case of slightly sloped portions, a slightly higher coefficient of friction may be desirable, while in the case of multiple lane to single lane portions, a very low coefficient of friction may be desirable. As previously mentioned, the application of a lubricant composition between the container and the conveyor belt surface with too high or too low a coefficient of friction can result in reduced system efficiency. The wet lubricant can meet the friction coefficient required by each part by adjusting the spraying time and flow rate. Dry lubricants are difficult to achieve in this regard. The coefficient of friction is relatively low for some time after the dry lubricant is sprayed, resulting in reduced transport efficiency for some parts where a higher coefficient of friction is required because the container "slips".

In the conventional wet lubricant, both soap-based lubricants and fatty amine-based lubricants have drawbacks, the former lubricating composition has no bacteriostatic properties and an additional bacteriostatic agent is required. The use of bacteriostats increases costs. And the friction coefficients required by different conveying belts are different, the dilution ratio is also different, and when the dilution ratio is high, the concentration of the bacteriostatic agent is reduced to a certain degree, so that the bacteriostatic effect is not achieved. The soap lubricant belongs to anionic surfactant and is not hard water resistant, so that in the use process, the pipeline of the lubricant is easy to produce dirt to block the pipeline and the nozzle. The latter has certain antibacterial function because fatty amine is equivalent to cationic surfactant in the presence of organic acid. When the pH value of the product stock solution is higher, the foam meets the requirement, but the fatty amine belongs to alkalinity, has higher alkalinity and is easy to cause the stress cracking of the PET bottle. Foam is not satisfactory at lower pH of the product stock. In recent years, wet lubricants have begun to develop in a nonionic direction, and their advantages are self-evident, such as hard water resistance, low foaming, no foaming, and low alkalinity. Nonionic surfactants are used as lubricating ingredients, mainly in polyether and polyethylene glycol applications. The aqueous solutions of polyethers have poor stability unless end-capped structures are used, but the cost of end-capped structures is high. Polyethylene glycol is used in dry lubricants in relatively few studies, but is more rarely reported between conveyor belts and containers in the field of application.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a wet lubricant for a conveyor belt and a preparation method thereof, wherein the lubricant is prepared by compounding polyethylene glycol and fatty alcohol alkylene oxide, has the characteristics of good lubricating effect and low foamability, can not corrode production equipment during use, and has higher hard water resistance and excellent antibacterial ability; the process is simple and feasible, and the prepared lubricant has good comprehensive performance and good market application prospect.

In order to achieve the above purpose, the present invention adopts the following technical scheme:

in a first aspect, the invention provides a wet lubricant for a conveyor belt, which is prepared from the following raw materials in percentage by mass: 1 to 10 percent of polyethylene glycol, 1 to 5 percent of nonionic surfactant, 0.1 to 10 percent of complexing scale inhibitor, 0.1 to 2 percent of bacteriostat and the balance of water.

As a further preferable aspect of the present invention, the polyethylene glycol has a molecular weight of 2000 to 150000; still more preferably, the polyethylene glycol has a molecular weight of 2000 to 22000.

It is understood that in the above technical scheme, polyethylene glycol is any combination of the molecular weights in the above interval (2000-150000, preferably 2000-22000), that is, can be a mixture of polyethylene glycols with different molecular weights, so long as the molecular weights are in the above interval; generally, when the molecular weight is less than 20000, it is called polyethylene glycol (PEG), and when the molecular weight is more than 20000, it is called polyethylene oxide (PEO).

As a further preferred aspect of the present invention, the polyethylene glycol is composed of PEG2000, PEG20000 and PEO 22000; still more preferably, the mass ratio of the PEG2000, the PEG20000 and the PEO22000 is 0.1-1:0.5-1:1-10; most preferably, the mass ratio of PEG2000, PEG20000 and PEO22000 is 1:1:3.

As a further preferable mode of the technical scheme, the nonionic surfactant is aliphatic alcohol alkylene oxide nonionic surfactant, specifically, a polymer formed by alkylene oxide monomers and aliphatic alcohol, wherein the alkylene oxide monomers are one or more of ethylene oxide, propylene oxide and butylene oxide.

Further preferred embodiments of the present invention include ethylene oxide copolymers and ethylene oxide/propylene oxide block copolymers.

As a further preferable mode of the technical scheme, the bacteriostat is one or more selected from quaternary ammonium salts, isothiazolinones, glyceryl monocaprylate, benzoate and glutaraldehyde, wherein the benzoate is butyl parahydroxybenzoate or methyl parahydroxybenzoate.

As a further preferred mode of the technical scheme of the invention, the bacteriostat is selected from one or two of quaternary ammonium salts and isothiazolinones; more preferably, isothiazolone is selected.

As a further preferable mode of the technical scheme of the invention, the complex scale inhibitor is selected from one or more of phosphates, amino carboxylates, hydroxycarboxylic acid salts, organic phosphoric acids, polyacrylic acids and alcohol amines; further preferably, the complex scale inhibitor is selected from one or two of amino carboxylate and organic phosphoric acid; more preferably, the complexing scale inhibitors are tetra sodium ethylenediamine tetraacetate (edta.4na) and hydroxyethylidene diphosphonic acid (HEDP).

In a second aspect, the invention provides a preparation method of the wet lubricant for the conveyor belt, which comprises the following specific steps:

sequentially adding polyethylene glycol, a nonionic surfactant, a bacteriostat and a first part of complex scale inhibitor into water, uniformly stirring, then adding another part of complex scale inhibitor, and regulating the pH value to be 4-6.

In the above technical scheme, the first part of the complexing scale inhibitor is tetra sodium ethylenediamine tetraacetate (edta.4na), and the second part of the complexing scale inhibitor is hydroxyethylidene diphosphonic acid (HEDP).

In a third aspect, the invention claims the use of a container lubricant for a conveyor as described above in a container conveyor system; in specific application, the application mode of the lubricant can be performed by referring to the application mode of the existing wet lubricant, water is used for dilution to form aqueous diluted lubricant solution when the lubricant is used, and a proportional dilution pump is used for conveying the diluted lubricant solution to a nozzle, and then the diluted lubricant solution is sprayed onto a chain plate through the nozzle; it will be appreciated that the manner of application of the lubricant is well established in the art and the process is not described in detail and is not specifically limited by the present invention.

Compared with the prior art, the invention has the following beneficial effects:

1. the lubricant does not take soap and amine surfactants as lubricating components, but takes a mixture obtained by compounding polyethylene glycol and fatty alcohol alkylene oxide as a lubricating component, and the mixture has the characteristics of good lubricating effect and low foamability; the wet lubricant disclosed by the invention can not corrode production equipment in use, and has higher hard water resistance and excellent antibacterial capacity; the use of the complex scale inhibitor eliminates the negative influence possibly caused by multivalent cations in water on the efficacy of the lubricant, and the dispersion scale inhibition effect of the complex scale inhibitor can effectively prevent dirt from accumulating on the inner wall of the lubricant pipeline in the long-term use process and keep the pipeline clean.

2. The choice of PEG molecular weight has a large impact on the performance of the lubricant. The lubricating oil also has good lubricating performance when the molecular weight is above 2000, and is widely applied to metal processing and textile industry; however, these applications are used in the original form of products, and for the wet lubricant for conveyor belts, the actual concentration is only tens to hundreds of ppm, and the molecular weight is about 2000, so that the requirements of the performance and the cost of the wet lubricant are hardly met; the invention discovers that when the molecular weight of PEG reaches more than 15000, the content of ppm level has good lubrication effect, and when the molecular weight is more than 20000, the viscosity of aqueous solution is large, thus having great limitation on the production and use of products; according to the invention, through reasonable selection, the polyethylene glycol consists of PEG2000, PEG20000 and PEO22000, so that the polyethylene glycol can exert the optimal lubrication effect while ensuring the production cost.

3. The wet lubricant obtained by the invention does not generate foam in use, and has high lubricity of the amine-containing water-based chain plate lubricant and low foamability of the amine-free water-based chain plate lubricant; the lubricant is slightly acidic, does not cause PET stress cracking, does not cause corrosion to production equipment, and has good comprehensive performance.

4. The raw material components of the lubricant are easy to obtain, the production process is simple to operate, the lubricant is prepared by simple stirring, heating is not needed, the time consumption is short, the production efficiency is high, the economic benefit is obvious, and the lubricant can be widely popularized and applied to industrial production.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the following examples. Of course, the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. It will be understood that the term "and/or" as used herein relates to and encompasses any and all possible combinations of one or more of the associated listed items.

It should be noted that PEG2000 in the examples is provided by Jiangsu sea Anamicalization, PEG20000 is provided by Shanghai doubly, PEO22000 is provided by Jiangsu Edgedbis chemical engineering Co., ltd., EM80 is provided by Shanghai ascending order, F108 Shanghai European culvert is provided, and EL90 is provided by Jiangsu sea Anamicalization; the specific conditions are not noted in the examples, and are carried out according to conventional conditions or conditions suggested by the manufacturer; the reagents or apparatus used were conventional products commercially available without the manufacturer's attention.

Example 1

The wet lubricant for the conveyor belt is prepared from the following raw materials:

the embodiment also provides a preparation method of the wet lubricant for the conveyor belt, which comprises the following specific steps:

according to the formula, PEO22000, EM80, isothiazolinone and EDTA.4Na are sequentially added into water, stirred into transparent liquid, HEDP is added, and the pH is adjusted to 4.5.

Example 2

according to the formula, PEO22000, F108, isothiazolinone and EDTA.4Na are sequentially added into water, stirred into transparent liquid, HEDP is added, and the pH is adjusted to 5.0.

Example 3

according to the formula, PEG2000, PEG20000, PEO22000, EM80, isothiazolinone and EDTA.4Na are sequentially added into water, the mixture is stirred into transparent liquid, HEDP is then added, and the pH is adjusted to 5.0.

Example 4

according to the formula, PEO22000, EL90, isothiazolinone and EDTA.4Na are sequentially added into water, stirred into transparent liquid, HEDP is added, and the pH is adjusted to 5.0.

Performance testing

The invention can be better understood by comparison tests. The lubricant of the present invention can be evaluated by friction coefficient, compatibility of the lubricant with PET, and alkalinity, concretely as follows:

coefficient of friction test

The lubricant friction coefficient measuring device of the present invention is described in patent document CN 210982181U. The frequency converter is regulated to drive the conveyer belt to run at the speed of 50-100 m/min, and the highest speed is 7-8 ten thousand bottles/hr. The lubricant is distributed on the surface of the conveying belt by using a nozzle, the tension meter is fixed on the measuring table, the beverage bottle of the measured object is placed on the conveying belt and is connected with the tension meter by using a rubber band, and the tension meter is connected with the computer by using a lead. The computer records the acting force exerted on the beverage bottle during the running process of the conveyor belt and calculates the friction coefficient. The lubricant compositions were continuously sprayed onto the conveyor belt at 1:200 and 1:500, respectively, and after 30 minutes of spraying, the coefficient of friction COF between the bottle and the conveyor belt was recorded for 1 minute.

Compatibility test of Lubricants with PET

The compatibility test of the lubricant of the present invention with PET was carried out as described in the PET stress cracking test section of patent document CN 101379173A. To a PET bottle (obtained from Baishi) filled with 557g of cooling water at 0 to 5℃were added 10.6g of baking soda and 17.1mL of a 50% aqueous solution containing citric acid. Immediately after the citric acid solution was added, the filled bottles were capped and the torque on the caps was adjusted to 16 in-lbs, then the bottles were rinsed with deionized water and stored at ambient conditions (20-25 ℃) overnight. 100 bottles thus filled with liquid were immersed in a 1:200 to 1:500 dilution of lubricant until the seam separating the bottles from the sidewall portion, and rotated for about 5 seconds. Move into a humidity chamber at 37.8 ℃ and with 85% relative humidity. The bins were checked daily and the number of failed bottles (broken) was recorded. On day 28, all test flasks were removed. The sample bottle had cracks giving a visual fine crack score to the bottle, where 0 = no apparent fine cracks, the bottle base was clear and transparent; whereas 10 = significant crazing, the bottle base was not clearly opaque.

Alkalinity test

100mL of lubricant sample is accurately measured, an MR indicator is added dropwise to the solution in the reagent to be measured, the solution is light green, the solution is titrated with 0.01M sulfuric acid until the color changes from light green to pink, and the total consumption of 0.01mol/L sulfuric acid solution volume V is recorded. Alkalinity m=v×10ppm.

The above performance tests were performed on the lubricants obtained in the examples of the present invention and on conventional commercially available lubricants (wherein commercially available Yikang LX210 is a non-ionic wet lubricant and commercially available D64 Tay Hua Shi is an amine wet lubricant), and the results are shown in Table 1 below:

TABLE 1 evaluation of Properties of lubricants and conventional commercially available lubricants obtained in examples of the present invention

Finally, it should be noted that: the above examples are not intended to limit the present invention in any way; modifications and improvements will readily occur to those skilled in the art upon the basis of the present invention; therefore, all changes, modifications, substitutions, combinations, and simplifications that may be made without departing from the spirit and principles of the invention are intended to be equivalent substitutes for those that are within the scope of the invention as defined by the appended claims.

Claims

1. The wet lubricant for the conveyor belt is characterized by being prepared from the following raw materials in percentage by mass: 1 to 10 percent of polyethylene glycol, 1 to 5 percent of nonionic surfactant, 0.1 to 10 percent of complexing scale inhibitor, 0.1 to 2 percent of bacteriostat and the balance of water.

2. The wet lubricant for conveyor belts according to claim 1, wherein the polyethylene glycol has a molecular weight of 2000 to 150000.

3. The wet lubricant for conveyor belts according to claim 2, characterized in that the polyethylene glycol consists of PEG2000, PEG20000 and PEO 22000.

4. The wet lubricant for conveyor belts according to claim 1, characterized in that the nonionic surfactant is a fatty alcohol alkylene oxide nonionic surfactant.

5. The wet lubricant for conveyor belt of claim 4, wherein the fatty alcohol alkylene oxide nonionic surfactant is a polymer of alkylene oxide monomers and fatty alcohol, wherein the alkylene oxide monomers are one or more of ethylene oxide, propylene oxide, and butylene oxide.

6. The wet lubricant for conveyor belts according to claim 1, wherein the bacteriostatic agent is one or more selected from the group consisting of quaternary ammonium salts, isothiazolinones, glyceryl monocaprylate, benzoates, glutaraldehyde.

7. The wet lubricant for conveyor belts according to claim 1, wherein the complex scale inhibitor is one or more selected from the group consisting of phosphates, aminocarboxylates, hydroxycarboxylic acids, organic phosphoric acids, polyacrylic acids, and alcamines.

8. The wet lubricant for conveyor belts of claim 7 wherein the complex scale inhibitor is tetra sodium ethylenediamine tetraacetate and hydroxyethylidene diphosphonic acid.

9. A method for preparing the wet lubricant for conveyor belts according to any one of claims 1 to 8, characterized by comprising the following specific steps:

10. Use of a wet lubricant for conveyor belts according to any one of claims 1 to 9 in a container conveyor system.