CN116445207B

CN116445207B - Container lubricant for conveyor belt and preparation method and application thereof

Info

Publication number: CN116445207B
Application number: CN202310414710.8A
Authority: CN
Inventors: 李洪阳; 徐文澜
Original assignee: Hubei Xikang Chemical Co ltd
Current assignee: Hubei Xikang Chemical Co ltd
Priority date: 2023-04-18
Filing date: 2023-04-18
Publication date: 2024-08-02
Anticipated expiration: 2043-04-18
Also published as: CN116445207A

Abstract

The invention discloses a container lubricant for a conveyor belt, which is prepared from the following raw materials: 0.01 to 5 percent of siloxane, 10 to 60 percent of humectant, 0.1 to 1 percent of bacteriostat, 0.1 to 1 percent of alkalinity regulator and the balance of water; wherein the siloxane is mainly octamethyl cyclotetrasiloxane and emulsified silicone oil, and the humectant is alcohol ether humectant; the lubricant composition contains a large amount of 'active' Si-OH which can react with a plastic chain plate, the retention time of a lubricating film is prolonged under the action of chemical bonds, and the addition of an alcohol ether humectant can avoid the condition that a conveyer belt in the existing dry film lubricant application interval is in a 'dry' state, so that the lubricating film has observability, the application interval can be adjusted in time, and the service time of the conveyer belt is prolonged.

Description

Container 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 container lubricant for a conveyer belt and a preparation method and application thereof.

Background

In the finished product packaging operation after filling of commercial containers, the containers are typically moved by a conveyor system at very high speeds, the conveyance being effected by movement of a chain flight of conveyor belts, the speed of which is evolving from 1 to 7-8 thousand bottles/hour with efficiency requirements. In order to ensure that the container is stable during movement, the chain plate needs to be lubricated. 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, and the friction coefficient of the lubricant is about 0.05 to 0.1 at 7 to 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. In particular, conveyor lubricants must meet the criteria for (1) PET (polyethylene terephthalate) compatibility, and for lubricants with higher alkalinity, PET bottles are prone to stress cracking. Since the lubricant adhered to the bottom of the container becomes high in alkalinity after drying, the polymer is broken by strong alkalinity, and thus is cracked. Thus, the total alkalinity of the lubricant composition is suitably less than about 100ppm CaCO ₃, preferably less than about 50ppm CaCO ₃, and most preferably less than about 30ppm CaCO ₃; (2) the environment surrounding the conveyor belt pipeline; (3) cost of lubricant and lubricant dispensing system equipment.

Conveyor belt lubricants fall into two modes, wet lubricants and dry lubricants. By wet lubricant is meant that the conveyor belt forms a diluted aqueous lubricant solution by diluting the concentrated lubricant composition with water (i.e., a dilution ratio of 1:50 to 1:1000), and a large amount of the diluted aqueous lubricant solution is delivered to the spray nozzles by means of the proportional dilution pump and sprayed onto the link plate by means of the spray nozzles. By dry lubricant is meant that the lubricant is supplied undiluted to the nozzle by a pumping device and sprayed onto the link plate by the nozzle. These lubricant compositions can reduce damage to containers or labels from high speed conveyor belt operation.

Since the wet lubricant requires a large amount of water, the amount of water discharged to the sewage treatment system is large; in use, it is inevitable that liquid is sprayed around the conveyor belt environment. As such, diluting the lubricant with large amounts of water results in wasted resources, is environmentally unfriendly and expensive. The presence of a moist surface and still water provides a medium for the growth of microorganisms including bacteria, yeasts and molds, etc. Ponding caused by excessive lubricant solution on the floor can easily cause people to slip. The water used to dilute the concentrated lubricant solution may in turn cause stress cracking of the (PET) 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.

The compatibility of the lubricant composition with PET bottles 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 PET bottles.

There are many ways of applying dry lubricants in actual use. In brief, there are two general ways of applying the lubricant to the conveyor belt, one is spraying the lubricant in mist form onto the conveyor belt through a nozzle, and the other is using a brush to transfer the lubricant to the conveyor belt through contact of the brush with the link plate. In view of cost and loss considerations, the pump is intermittently turned on, typically for 10 seconds, and stopped for 30 to 60 minutes. Too short a pump on time and too long an interval to spray lubricant composition, the lubrication between the conveyor belt and the containers being transported on the conveyor belt may be insufficient. Too much lubricant composition is sprayed for too long a pump on time and too short an interval, again leading to lubricant loss and increased costs. The prior art methods have only sought to minimize the amount of lubricant composition used, however, none of the various modes of application and compositions of lubricant solve a problem, the dry lubricant (including some other so-called semi-dry or semi-wet) is applied to the belt flights in very small amounts, long application intervals, the moisture in the lubricant volatilizes, and the flights are prevented from being in an extremely "dry" state, i.e., the flight surfaces appear dry, which is probably one of the sources of dry lubricant names. During the operation of the conveyor belt, the lubricating film of the upper sections of the link plates is inevitably destroyed, so that the lubrication of the link plates at these positions is in failure, and the link plates are worn out severely without lubrication although the efficiency of the whole system is not reduced. Since the link plate is in a "dry" state, the damage of the lubricating film is not observable, and the application adjustment cannot be performed by observation. In reality, after such a long-term operation of the conveyor belt, the conveyor belt may break.

Disclosure of Invention

In view of the shortcomings of the prior art, the present invention aims to provide a container lubricant for conveyor belts and a preparation method thereof, which not only meets the necessary standards of conveyor belt lubricants, but also can generate a proper friction coefficient between a container and the surface of a conveyor belt, and has proper total alkalinity and good PET compatibility, and more importantly, the use cost of the container lubricant is far lower than that of the prior product; the lubricating film formed after the lubricant is applied to the conveyer belt is not easy to damage, the lubricating film can be kept for a long time, and the service performance is far better than that of the existing product. The damage of the lubricating film is observable, and the application adjustment can be performed by observation.

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

In a first aspect, the invention provides a container lubricant for a conveyor belt, which is prepared from the following raw materials in percentage by mass: 0.01 to 5 percent of siloxane, 10 to 60 percent of humectant, 0.1 to 1 percent of bacteriostat, 0.1 to 1 percent of alkalinity regulator and the balance of water.

Specifically, the siloxane may comprise any of 0.01%, 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5% or 0.01% to 5%; the humectant may comprise 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60% or any particular value from 10% to 60%; the bacteriostat can be any specific value in 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1% or 0.1% -1%; the alkalinity regulator may comprise any particular value from 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1% or from 0.1% to 1%.

As a further preferable aspect of the present invention, the siloxane is one or more selected from dimethyl cyclic siloxane (DMC), hexamethyldisiloxane (MM), octamethyl cyclic tetrasiloxane (D4), decamethyl cyclic pentasiloxane (D5), and emulsified silicone oil; further preferably, the siloxane is selected from one or more of octamethyl cyclotetrasiloxane (D4), decamethyl cyclopentasiloxane (D5) and emulsified silicone oil; still more preferably, the siloxane is octamethyl cyclotetrasiloxane (D4) and a silicone emulsion.

As a further preferable mode of the technical scheme, the humectant is an alcohol ether humectant, and specifically, the humectant is one or more selected from ethylene glycol, polyethylene glycol, glycerol, diethylene glycol, triethylene glycol, tetraethylene glycol, ethylene glycol butyl ether and diethylene glycol butyl ether; further preferably, the humectant is selected from one or more of ethylene glycol, polyethylene glycol, glycerol, diethylene glycol; still more preferably, the humectant is polyethylene glycol and glycerin.

As a further preferred aspect of the present invention, the polyethylene glycol is a low molecular weight polyethylene glycol having a molecular weight of less than 600, preferably polyethylene glycol 200.

As a further preferred mode of the technical scheme of the invention, the bacteriostat is selected from one or more of quaternary ammonium salts, isothiazolinones, glyceryl monocaprylate, benzoate esters and glutaraldehyde esters, wherein the benzoate esters are selected from one or two of butyl parahydroxybenzoate and methyl parahydroxybenzoate; further preferably, the bacteriostatic agent is selected from one or two of quaternary ammonium salts and isothiazolinones.

As a further preferred aspect of the present invention, the alkalinity regulator is selected from one or more of organic carboxylic acids, phosphoric acid, hydrochloric acid, sulfuric acid, wherein the organic carboxylic acids are selected from one or two of formic acid and acetic acid; further preferably, the alkalinity regulator is selected from one or two of acetic acid and phosphoric acid; more preferably, the alkalinity regulator is acetic acid.

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

adding siloxane into emulsified silicone oil, stirring uniformly, adding a humectant, stirring uniformly, adding water, stirring uniformly, adding a bacteriostat and an alkalinity regulator, and stirring uniformly to obtain the container lubricant for the conveyor belt.

As a further preferable mode of the technical scheme of the invention, the siloxane is added into the emulsified silicone oil and then stirred at a high speed, the rotating speed of the stirrer is 1000-3000 r/min, and the stirring time is 5-20 min.

The production process of the lubricant has simple operation, needs no heating by simple stirring, has short time consumption and high production efficiency,

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 dry lubricant, for example, the lubricant can be sent to a nozzle through a pumping device and then sprayed onto a conveying belt through the nozzle, or the lubricant can be conveyed onto the conveying belt through the contact of the brush and a chain plate by using the brush; it will be appreciated that the manner of application of the lubricant is an existing well established process known to those skilled in the art and the process will not be described in detail herein.

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

1. The lubricant provided by the invention can generate proper friction coefficient (0.09-0.11) between the container and the surface of the conveyer belt during application, has proper total alkalinity (60) and good PET compatibility, meets the necessary standard of the conveyer belt lubricant, and more importantly, the use cost is far lower than that of the prior product, so the lubricant has great significance; the N value (the ratio of the time T of lubricant application to the time T ₀ of no application) of the lubricant provided by the invention is far smaller than that of the existing product, and the definition of the N value shows that the smaller the N value is, the smaller the relative time of application is, which indicates that the better the lubricant performance is and the lower the use cost is. The N value is creatively provided by the invention and can be used as a standard for evaluating the performance of the dry lubricant.

2. The lubricating film formed by the conventional dry lubricants such as silicon emulsion is easily damaged in the running process of the conveyer belt, and the lubricant provided by the invention effectively solves the problem; the possible reason is that after the conventional dry lubricant such as silicon emulsion is applied to the conveyor belt, a lubricating film is formed on the chain plate through adsorption, the film formed by adsorption does not form chemical bonds with the chain plate, and the film is easily taken away by a container in the operation of the conveyor belt, so that the lubricating film is abraded, and the lubricant needs to be applied periodically; the applicant found that the more the silicone in the silicone emulsion type lubricant contains "active" Si-OH, the longer the interval of lubricant application, indicating that the lubricant film is less prone to "wear", which may be the phenomenon that the "active" Si-OH undergoes condensation reaction with the plastic link plate under some unknown conditions, the effect of the chemical bond causes the lubricant film to be less prone to be carried away by the container, and the retention time is prolonged; the octamethyl cyclotetrasiloxane (D4) in the lubricant composition of the present invention contains a large amount of "active" Si-OH, and is more reactive with plastic conveyor belts than other Si-OH, thereby making the performance of the lubricant composition far superior to that of the existing products.

3. Furthermore, the alcohol ether humectant is added into the lubricant composition, so that the state that the conveyer belt is in a dry state in the existing dry film lubricant application interval is changed, the lubricating film is observable, the application interval can be adjusted in time, and the service time of the conveyer belt is prolonged.

4. The raw material components of the lubricant are easy to obtain, the production process is simple to operate, the time consumption is short, the production efficiency is high, the economic benefit is obvious, and the lubricant can be widely 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, in the examples, specific conditions are not specified, and the examples are performed under conventional conditions or conditions recommended by the manufacturer; the reagents or apparatus used were conventional products commercially available without the manufacturer's attention.

Example 1

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

The embodiment also provides a preparation method of the container lubricant for the conveyer belt, which comprises the following specific steps: according to the formula, adding D4 into AF409, stirring uniformly, then adding a humectant consisting of PEG200 and glycerin, stirring uniformly, wherein the solution is transparent liquid, then adding water, stirring uniformly, finally adding pinus koraiensis and acetic acid, and stirring uniformly to obtain the container lubricant for the conveyor belt.

Example 2

Example 3

Comparative example 1

The embodiment also provides a preparation method of the container lubricant for the conveyer belt, which comprises the following specific steps: according to the formula, AF409 is added into a humectant consisting of PEG200 and glycerin, and is stirred uniformly, at the moment, the solution is transparent liquid, then water is added, and is stirred uniformly, and finally, the kathon and acetic acid are added, and the container lubricant for the conveyer belt is obtained after being stirred uniformly.

Comparative example 2

The preparation and preparation method of the raw material components of the lubricant are carried out according to the embodiment 1 of the patent document CN101955844B, and specifically comprises the following steps:

according to the formula, dimethicone, fatty alcohol polyoxyethylene ether AEO4, alkyl glucoside APG0810, dodecanol, oleic acid, alkyl glucoside APG0810, sodium dodecyl sulfate and methyl parahydroxybenzoate are mixed together, heated to 70-75 ℃, 70g of deionized water which is added with 70 ℃ in advance is slowly added under uniform stirring, uniformly stirred and emulsified to form water-in-oil (w/o) emulsion, 65g of deionized water which is approximately 70 ℃ is slowly added, continuously uniformly stirred for 5 minutes at 65-70 ℃ to form white emulsion, so that the formed water-in-oil (w/o) emulsion is gradually converted into oil-in-water (o/w) emulsion, finally, the rest 65g of normal-temperature deionized water is added, continuously uniformly stirred for 10 minutes, then high-speed stirring is turned off, cooling to below 30 ℃ by adopting ordinary mechanical stirring, and the milky oil-in-water (o/w) emulsion lubricant is obtained after filtering to remove impurities.

Performance testing

The invention can be better understood by comparison tests. The lubricants of the present invention can be evaluated by coefficient of friction, basicity, compatibility of the lubricant with PET, and the ratio of time the lubricant is applied to not applied (actual in-situ test), 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 was applied for 10 seconds, stopped for 60 minutes, repeated 3 times, and the coefficient of friction COF between the bottle and the conveyor belt was recorded at the end of the stopped application for 60 minutes after 3 times of repetition, for 1 minute.

Compatibility test of Lubricants with PET

The compatibility test of the lubricant of the present invention with PET was carried out in accordance with the content of the PET stress cracking test section described in 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 the lubricant working liquid and rotated for about 5 seconds until the joint separating the bottle body from the sidewall portion was reached. 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.

Test of the ratio of time (T ₀) of lubricant application to non-application

In the simulation test of friction coefficient in a laboratory, a plurality of conditions inconsistent with a production field exist, and the most basic is that the chain plate of the conveying belt is uneven due to abrasion, and the conveying belt in the laboratory is a surface with good flatness; the transmission of the conveyer belt to the container makes a large number of beverage bottles pass through one point on the chain plate in each hour, and 7-8 ten thousand beverage bottles are reached in many times, and the lubricant adsorbed on the conveyer belt can be taken away by a large number of beverage bottles, so that the lubricant film is slowly worn and thinned, and the amount of the lubricant on the conveyer belt is dynamically reduced. While the laboratory test beverage bottles were fixed in number and the amount of lubricant on the conveyor belt was relatively static. Laboratory tests can only be used as reference data and cannot be used for explaining the actual use condition. Therefore, the present invention is applied to a production site, and the results of such tests can truly reflect the performance of the lubricant composition. In a specific test, two black upright posts are arranged at one end of the conveying belt, a workbench as in a patent CN210982181U is arranged on each upright post, a tension meter is fixed on the workbench, a beverage bottle to be tested is placed on the conveying belt and is connected with the tension meter through a rubber band, and the tension meter is connected with a computer through a wire. 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 coefficient of friction was measured once after 60 minutes of application, each time for 60 seconds. When the friction coefficient is in the range of 0.05-0.15, no lubricant is applied, measurement is continued until the friction coefficient is not in the range of 0.05-0.15, the accumulated time T ₀ is counted, and the non-application time of the application device is adjusted to be T ₀. General dry lubricant T: t ₀ ratio is between 1:180 and 1:720. Continuously adjusting T ₀ and T during testing, and continuously testing to obtain a limit T: t ₀ is the value N.

The lubricants obtained in the examples and comparative examples of the present invention were subjected to the above performance test, and the results are shown in table 1 below:

TABLE 1 evaluation of the Properties of the Lubricants obtained in the examples of the present invention and comparative examples

Sample of	COF	M	PET compatibility	T:T₀(N)
					Example 1	0.11	50	Disqualified 1 bottle, crack scoring 5 points	1:5000
Example 2	0.11	60	Disqualified 1 bottle, crack score 6 points	1:3500
					Example 3	0.09	30	Failure 1 bottle, crack score 3 points	1:14000
Comparative example 1	0.13	80	Failure 1 bottle, crack score 8 points	1:700
					Comparative example 2	0.12	60	Failure 1 bottle, crack score 8 points	1:900

From the data in Table 1, it can be seen that the N value of the lubricant of the present invention is far smaller than that of the comparative example, and that the smaller the N value, the smaller the relative time it takes to apply, and the lower the cost of use. In practical applications, regarding T of dry film lubricant: t ₀ is a value N, and the N value of the existing products on the market can reach a basically stable value approximately in 2 days during testing, and most of the products are about 1:500-1:1000. The N value of the invention can be generated only by 15 days, and the N value is far smaller than that of the existing product. The N value of the lubricant according to the invention is obtained for a long time because the reaction of Si-OH with the plastic link plate is slow and also depends on the Si-OH content in the lubricant composition according to the invention. In the composition of the invention, the Si-OH in D4 is "reactive" and reacts more readily with the plastic conveyor belt than other Si-OH, thus making its properties far exceeding those of the prior art.

It is because the present invention finds that the more "reactive" Si-OH the siloxanes in the silicone emulsion class contain, the longer the application time is. Besides meeting the necessary standard of conveyor belt lubricants, the use cost of the invention is far lower than that of the prior products, and the invention has great significance. In addition, the invention changes the dry state of the conveyer belt in the existing dry film lubricant application interval except the N value, so that the lubricant film has observability, the application interval can be adjusted in time, and the service time of the conveyer belt is prolonged.

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 container lubricant for the conveyor belt is characterized by being prepared from the following raw materials in mass: 2.0g of emulsified silicone oil, 0.1g of octamethyl cyclotetrasiloxane, 10g of PEG200, 40g of glycerol, 0.2g of kathon, 0.1g of acetic acid and 47.6g of water.

2. A method of preparing the container lubricant for conveyor belts of claim 1, characterized by the specific steps of: adding siloxane into emulsified silicone oil, stirring uniformly, adding a humectant, stirring uniformly, adding water, stirring uniformly, adding a bacteriostat and an alkalinity regulator, and stirring uniformly to obtain the container lubricant for the conveyor belt.

3. Use of the container lubricant for conveyor belts of claim 1 in a container conveyor system.