CN109943151B - Environment-friendly nano dust-free chalk and preparation method thereof - Google Patents
Environment-friendly nano dust-free chalk and preparation method thereof Download PDFInfo
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Abstract
The invention relates to the field of cultural and educational supplies and stationery supplies, in particular to environment-friendly nanometer dust-free chalk and a preparation method thereof. The invention relates to an environment-friendly nanometer dust-free chalk, which at least comprises the following components in parts by weight: 50-80 parts of titanium dioxide and 1-15 parts of white oil; 1-12 parts of paraffin; 20-55 parts of an auxiliary agent; wherein the auxiliary agent consists of modified starch, monoglyceride and silicone oil. The dustless chalk has the advantages that through the mutual synergistic effect of the components such as titanium dioxide, white oil, paraffin, an auxiliary agent and the like, the quality is fine and flexible, the writing is smooth, and the breakage is not easy to occur; the total dust concentration of the chalk is greatly reduced by controlling the proportion of each component. Moreover, the dust-free chalk does not contain toxic and volatile substances, has good weather resistance and long service life, and is beneficial to the improvement of the teaching environment.
Description
Technical Field
The invention relates to the field of cultural and educational supplies and stationery supplies, in particular to environment-friendly nanometer dust-free chalk and a preparation method thereof.
Background
The chalk is an indispensable cultural article in daily teaching, and is widely used due to the advantages of clear and intuitive fonts, easy writing and erasing, low price and the like. Gypsum powder is the most widely used raw material for making chalk, and is the white base material of chalk and the binder for forming chalk. But the gypsum chalk has pores and small density (0.8-1.0 g/cm)3) The chalk is used for preparing common chalk, dust flies greatly in the using process, the body health of teachers and students is seriously harmed, and the environmental sanitation is influenced.
In order to improve the teaching environment and the use performance of chalks, dust-free chalks are widely used at home and abroad at present to solve the problem of dust pollution. At present, dust fall ways of home and abroad chalks mainly have two aspects: (1) increasing the weight of the powder; by adding grease or polyalcohol as binder and adding large specific gravity filler, the specific gravity and volume of the dust are increased, and the dust is not easy to disperse. (2) The abrasion resistance of the chalk is increased (the friction is reduced). For example, patent No. 201510919174.2 discloses a green and environment-friendly dust-free chalk prepared by adding a dust-proof agent, a higher fatty alcohol sulfate surfactant, medical stone powder, a processing aid and the like into gypsum powder; according to the patent with the application number of 201310386442.X, the environment-friendly dust-free chalk which is fluent in writing, clear in writing, moderate in hardness and less in dust is prepared by adding white powder, polyvinyl acetate emulsion, polyvinyl alcohol and the like into plaster. According to the patent with the application number of 200910011700.X, illite powder, glycerin, a surfactant, essential oil, edible oil, paraffin, plant palm oil and the like are added to prepare the biochemical chalk which does not generate dust and can be wiped clean by using a wet cloth. In fact, dust-free chalk still generates more or less dust because chalk writing is written by covering dust, but the dust amount is greatly reduced compared with that of ordinary chalk. Furthermore, the mechanical strength of the chalk is reduced by adding a binder such as grease.
Disclosure of Invention
In order to solve the technical problems, the invention provides an environment-friendly nano dust-free chalk, which at least comprises the following components in parts by weight:
wherein the auxiliary agent consists of modified starch, monoglyceride and silicone oil.
As a preferred technical scheme, the titanium dioxide is rutile titanium dioxide.
As a preferable technical scheme, the particle size of the rutile type titanium dioxide is 50-500 nm.
As a preferable technical scheme, the modified starch, the monoglyceride and the silicone oil have the following weight parts:
20-30% of modified starch;
60-70% of monoglyceride;
10-20% of silicone oil.
As a preferred technical scheme, the modified starch is sodium starch octenyl succinate.
As a preferable technical scheme, the monoglyceride is at least one of glyceryl oleate, glyceryl linoleate, glyceryl palmitate, glyceryl behenate, glyceryl stearate, glyceryl laurate and glyceryl linolenate.
As a preferred technical scheme, the monoglyceride is glyceryl palmitate.
As a preferable technical scheme, the silicone oil is hydroxyphenyl silicone oil.
As a preferable technical scheme, the mass fraction of hydroxyl in the hydroxyphenyl silicone oil is 1-10%.
The second aspect of the invention provides a preparation method of the dust-free chalk, which at least comprises the following steps:
s1, adding white oil and paraffin into a stirring container in sequence, stirring for 1-2 hours at a rotating speed of 1500-2500 rpm and a temperature of 70-100 ℃;
s2, sequentially adding titanium dioxide and an auxiliary agent into the stirring container in the step S1, stirring for 1.5-2 hours at the rotating speed of 1500-2500 rpm and the temperature of 80-100 ℃;
s3, injecting the mixture obtained in the step S2 into a mold, pressing, cooling, cutting into finished products, and packaging.
Has the advantages that: the dustless chalk has the advantages that through the mutual synergistic effect of the components such as titanium dioxide, white oil, paraffin, an auxiliary agent and the like, the quality is fine and flexible, the writing is smooth, and the breakage is not easy to occur; the total dust concentration of the chalk is greatly reduced by controlling the proportion of each component. Moreover, the dust-free chalk does not contain toxic and volatile substances, has good weather resistance and long service life, and is beneficial to the improvement of the teaching environment.
Detailed Description
For purposes of the following detailed description, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. Moreover, other than in any operating examples, or where otherwise indicated, all numbers expressing, for example, quantities of ingredients used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
When a range of values is disclosed herein, the range is considered to be continuous and includes both the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values of the range is included. Further, when multiple range-describing features or characteristics are provided, the ranges may be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. For example, a stated range from "1 to 10" should be considered to include any and all subranges between the minimum value of 1 and the maximum value of 10. Exemplary subranges of the range 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, 5.5 to 10, and the like.
In order to solve the problems, the invention provides an environment-friendly nano dust-free chalk, which at least comprises the following components in parts by weight:
wherein the auxiliary agent consists of modified starch, monoglyceride and silicone oil.
As a preferred embodiment, the dust-free chalk at least comprises the following components in parts by weight:
titanium white powder
Titanium dioxide is a polycrystalline inorganic compound, and the main component of the titanium dioxide is TiO2。TiO2Is a polycrystalline compound with dots arranged regularly. It is a kind of acidic amphoteric oxide with very stable chemical property. Hardly reacts with other elements and compounds at normal temperature, does not act on oxygen, ammonia, nitrogen, hydrogen sulfide, carbon dioxide and sulfur dioxide, and is insoluble in waterFat, which is insoluble in dilute acid, inorganic acid and alkali, and only in hydrofluoric acid. Under the action of light, the titanium dioxide can generate continuous oxidation-reduction reaction and has photochemical activity.
The titanium dioxide in the application can be prepared by a sulfuric acid method. The sulfuric acid method is characterized in that sulfuric acid is used as a main raw material for producing titanium dioxide, firstly, a titanium sulfate solution is obtained, and most of impurity iron elements in the solution are removed through reduction and vacuum crystallization; heating the titanium liquid to a temperature close to boiling temperature to hydrolyze the titanium sulfate solution to obtain metatitanic acid precipitate; filtering the metatitanic acid precipitate to remove most of waste acid and harmful metal impurities; then, removing most of impurity metal elements in the metatitanic acid by one-to-two water washing; adding proper salt treating agent into metatitanic acid, filtering to remove most of water, and calcining metatitanic acid filter cake in a brick kiln to obtain primary titanium dioxide product. And carrying out post-treatment on the primary product to obtain a titanium dioxide product.
The titanium dioxide in the application can also be prepared by a chlorination method. The chlorination process is a process using chlorine gas as a main raw material. Firstly, hydrochloric acid or smelting is used for removing iron element in ilmenite to obtain a titanium raw material with high titanium content; then reacting the coke and chlorine with a titanium raw material to generate titanium tetrachloride; heating and purifying, and reacting with oxygen at high temperature to obtain rutile type titanium dioxide primary product. The rutile type titanium dioxide product is obtained by post-treatment of the primary products.
The titanium dioxide has three crystal forms, namely rutile type titanium dioxide, anatase type titanium dioxide and plate type titanium dioxide. Wherein, the plate-shaped titanium white powder is a very unstable crystal form, belongs to an orthorhombic system, and the crystal lattice consists of 8 units of TiO2And (4) forming. When the temperature rises to about 650 ℃, the plate-type titanium dioxide is converted into rutile-type titanium dioxide. At the temperature of 200-600 ℃, the plate-type titanium dioxide can be prepared by adopting alkyl titanium or sodium titanate and potassium hydroxide or sodium hydroxide as raw materials. The anatase titanium dioxide is a tetragonal crystal system, and the crystal lattice is formed by 4 units of TiO2The composition, diffraction angle is 25.5 degrees, and the shape is approximately regular octahedron. The rutile type titanium dioxide is a tetragonal crystal system, and the crystal lattice is formed by 2 units of TiO2Composition, diffraction angle 27.5 degrees, with fine and long crystals and rhombus shape.
As a preferred embodiment, the titanium dioxide is rutile type titanium dioxide.
In a preferred embodiment, the particle size of the rutile titanium dioxide is 50-500 nm.
Preferably, the particle size of the rutile titanium dioxide is 200-260 nm.
The titanium dioxide (model: BR638) is purchased from Hebei Bofeng chemical Co., Ltd.
White oil
White oil, also known as paraffin oil and mineral oil, is colorless, odorless, chemically inert and has good light stability. The white oil has a saturated hydrocarbon structure, is obtained by subjecting a high-boiling fraction (i.e., a lubricating oil fraction) obtained by petroleum fractionation to dewaxing, carbonization, neutralization, and activated clay refining, and is a mixture of liquid hydrocarbons, mainly a mixture of n-isoparaffins having C16 to C31, and contains approximately zero aromatic hydrocarbons, nitrogen, oxygen, sulfur, and the like. The white oil has good oxidation stability, chemical stability and light stability.
In a preferred embodiment, the kinematic viscosity of the white oil is 10 to 50mm2/s。
Preferably, the kinematic viscosity of the white oil is 12-16 mm2/s。
In the application, the kinematic viscosity of the white oil is determined by referring to the method of GB/T265-1988. The measuring step is that at the temperature of 40 ℃, a certain volume of white oil flows through the time of a calibrated glass capillary viscometer under the gravity, and the product of the capillary constant and the flow time of the viscometer is the kinematic viscosity of the white oil at the temperature of 40 ℃.
In this application, the white oil (model # 15) was purchased from Nissu oil Co., Ltd, Wuxi.
Paraffin wax
The paraffin is also called crystal wax, hydrocarbon mixture with 18-30 carbon atoms, and has straight chain paraffin (about 80-95%), and small amount of paraffin with individual branch chain and monocyclic naphthene with long side chain (the total content of both is below 20%). The paraffin is a flaky or needle crystal prepared by refining a lubricating oil fraction obtained by distilling crude oil with a solvent, dewaxing the lubricating oil fraction with the solvent or freezing and crystallizing the paraffin, squeezing and dewaxing the lubricating oil fraction to obtain a cerate, deoiling the cerate, and supplementing and refining the wax.
Herein, the paraffin wax includes at least one of microcrystalline wax, liquid paraffin wax, and polyethylene wax.
The microcrystalline wax is a mineral wax with high molecular weight and high melting point, and has higher branched alkane and cyclic alkane. The microcrystalline wax has good toughness and low permeability to water vapor. The solid is colorless to white massive solid at normal temperature, is odorless and tasteless, and has a melting point of 60-85 ℃.
The liquid paraffin is paraffin containing normal paraffin obtained by using kerosene or diesel oil fraction as a raw material and performing adsorption separation by a molecular sieve or dewaxing by isopropanol-urea; or liquid paraffin synthesized in the coal/natural gas liquefaction process.
The polyethylene wax refers to low molecular weight polyethylene with molecular weight of 1500-25000 or partially oxidized low molecular weight polyethylene. It is in the form of granule, white powder, block and milky wax. Has excellent flowability, electrical performance and demolding performance.
In a preferred embodiment, the paraffin wax is a microcrystalline wax.
Preferably, the microcrystalline wax is an oxidized microcrystalline wax.
The preparation method of the oxidized microcrystalline wax comprises the following steps:
(1) adding 10g of microcrystalline wax into a reaction kettle, and heating to melt;
(2) adding 50mg of catalyst manganese acetate and 1.2g of auxiliary agent stearic acid, introducing oxygen with the flow rate of 70-80 mL/min, and reacting at 150 ℃ for 2-10 h to obtain the oxidized microcrystalline wax.
In a preferred embodiment, the acid value of the oxidized microcrystalline wax is 5-30 mg KOH/g.
Preferably, the acid number of the oxidized microcrystalline wax is 10mg KOH/g.
In the present application, the method for determining the acid value of the oxidized microcrystalline wax comprises the following steps:
(1) putting 1.0000g of oxidized microcrystalline wax into a 250mL triangular flask, adding 40mL of dimethylbenzene, and heating to melt;
(2) adding 3-5 drops of 1% phenolphthalein solution, titrating with 0.5mol/L KOH-ethanol solution until the titrated hot solution is peach-red, and if wax precipitation is found during titration, heating the sample again, and titrating as quickly as possible. And the ml of KOH-ethanol solution used is recorded.
Wherein the calculation formula of the acid value is as follows: acid value (V)KOH×NKOH-ethanol×56.1)/W(sample)。VKOHVolume of KOH-ethanol solution consumed; n is a radical ofKOH-ethanolThe concentration of KOH-ethanol solution; w(sample)Is the mass of the microcrystalline wax.
In the application, the oxidized microcrystalline wax has a solidification effect and a good emulsification effect, can promote the dispersion of titanium dioxide in an oily system and increase the toughness of chalk, and particularly when the acid value of the oxidized microcrystalline wax is 5-30 mg KOH/g. When the acid value is higher, the color of the oxidized microcrystalline wax is yellowish, and the use of the chalk is influenced.
In one embodiment, the adjuvant consists of modified starch, monoglyceride and silicone oil.
Modified starch
Starch is a natural high molecular compound of polysaccharide substances formed by polycondensation of glucose, is a renewable substance with the most abundant natural sources, is degradable, and cannot cause pollution to the environment. A large number of reactive hydroxyl groups exist in the molecular chain, so that a structural basis is provided for the modification of the starch. The modified starch is prepared by introducing new functional groups on starch molecules or changing the size of the starch molecules and the properties of starch granules by physical, chemical or enzymatic treatment on the basis of the inherent characteristics of the natural starch, so as to improve the performance of the starch and expand the application range of the starch, thereby changing the natural characteristics of the starch and enabling the starch to be more suitable for the requirements of certain applications.
In a preferred embodiment, the modified starch is sodium starch octenyl succinate.
The sodium starch alkenyl succinate in the application is white powder, non-toxic and free of peculiar smell. Sodium starch octenyl succinate is prepared by esterifying starch and octenyl succinic anhydride, and optionally treating with enzyme, dextrinization, acid, and bleaching.
In the application, the titanium dioxide has the advantages of high refractive index, good weather resistance, high whiteness and the like, but the titanium dioxide is difficult to disperse in an oily system due to more hydroxyl groups on the surface of the titanium dioxide. The applicant finds that the addition of sodium starch octenyl succinate can improve the dispersibility of titanium dioxide in an oily system, thereby increasing the content of the titanium dioxide. Starch octenyl succinate has a content of 1: 1, polar and nonpolar groups on the one hand, the polar groups on the starch octenyl succinate with TiO2Forming strong interaction force; on the other hand, the interaction of the nonpolar group on the octenyl succinic acid starch ester and the oily system promotes the dispersion of the titanium dioxide in the oily system.
Monoglyceride
In the present application, the term "monoglyceride" is a monoglyceride of fatty acids.
In the application, the fatty acid monoglyceride contains a lipophilic long-chain alkyl group and two hydrophilic hydroxyl groups, and has good surface activity.
In a preferred embodiment, the monoglyceride is at least one of glyceryl oleate, glyceryl linoleate, glyceryl palmitate, glyceryl behenate, glyceryl stearate, glyceryl laurate and glyceryl linolenate.
The applicant finds that the addition of sodium starch octenyl succinate can improve the dispersibility of titanium dioxide in an oily system, but the titanium dioxide contains a larger cyclic structure, so that the emulsifying speed is low, and the emulsifying effect is not ideal. And the arrangement speed of molecular chains is slow due to the large ring-shaped structure in the starch sodium octenyl succinate molecule, so that the formed micelles are loose, and have larger particle size and poorer stability. The applicant finds that after the fatty acid monoglyceride is added, the emulsifying speed of the octenyl succinic acid starch sodium can be accelerated, and the stability of the emulsifier is improved. The applicant believes that the possible reasons are that fatty glyceride has a longer molecular chain structure, the chain segment is easy to rotate and change the conformation, the migration speed of the hydrophilic group and the hydrophobic group in an inorganic matter and an oil phase system is higher, so that a looser interface film is formed at a higher speed, and the cavity generated by the movement of the fatty glyceride can supply the movement of the ring structure in the starch sodium octenyl succinate and the speed of adsorption on the inorganic matter, so that the emulsifying speed is increased.
In addition, under the irradiation of ultraviolet rays, electrons on the surface of the titanium dioxide powder can generate transition, so that oxygen atoms on crystal lattices lose two electrons, nascent oxygen with a strong oxidation effect is formed, organic substances in contact with titanium dioxide can be oxidized, the performance of surrounding organic media is changed, the toughness of the chalk is poor, the chalk is easy to break, and the use performance of the chalk is affected. The applicant has unexpectedly found that the addition of sodium starch octenyl succinate and fatty acid monoglyceride improves the weatherability of chalk to some extent. The possible reasons are: the sodium starch octenyl succinate and the fatty acid monoglyceride form a coating effect around the titanium dioxide, and electrons on the surface of the titanium dioxide are prevented from generating transition to generate nascent oxygen.
In a preferred embodiment, the monoglyceride is a palmitic acid glyceride.
Silicone oil
Silicone oil generally refers to a linear polysiloxane product that remains in a liquid state at room temperature. Generally, the silicone oil is classified into methyl silicone oil and modified silicone oil. The most commonly used silicone oil is methyl silicone oil, all organic groups of the methyl silicone oil are methyl, and the methyl silicone oil has good chemical stability, insulating property and hydrophobic property. It is prepared through hydrolysis of dimethyldichlorosilane in water to obtain initial condensed ring body, cracking and rectifying to obtain low ring body, mixing the ring body, sealing agent and catalyst together to obtain various mixture with different polymerization degree, and vacuum distillation to eliminate low-boiling point matter to obtain silicone oil. The silicone oil has excellent heat resistance, electric insulation, weather resistance, hydrophobicity, physiological inertia and smaller surface tension, and in addition, has low viscosity-temperature coefficient, higher compression resistance, and some varieties also have radiation resistance. The silicone oil has many special properties, such as oxidation resistance, high flash point, small volatility, no corrosion to metal, no toxicity and the like.
According to the chemical structure, methyl silicone oil, ethyl silicone oil, phenyl silicone oil, methyl hydrogen-containing silicone oil, methyl phenyl silicone oil, methyl chlorphenyl silicone oil, methyl ethoxy silicone oil, methyl trifluoro propyl silicone oil, methyl vinyl silicone oil, methyl hydroxy phenyl silicone oil, ethyl hydrogen-containing silicone oil, hydroxyl hydrogen-containing silicone oil, cyanogen-containing silicone oil and the like are classified; according to the application, damping silicone oil, diffusion pump silicone oil, hydraulic oil, insulating oil, heat transfer oil, brake oil and the like are available. It is often used as high-grade lubricating oil, shock-proof oil, insulating oil, defoaming agent, demoulding agent, polishing agent and vacuum diffusion pump oil, etc. Among various silicone oils, methyl silicone oil is most widely used, and is the most important variety of silicone oils, and methyl phenyl silicone oil is the second choice. Further, ethyl silicone oil, methylphenyl silicone oil, nitrile-containing silicone oil and the like are also available. The modified silicone oil can have special properties through modification of the silicone oil.
In a preferred embodiment, the silicone oil is a hydroxyphenyl silicone oil.
The preparation method of the hydroxyphenyl silicone oil comprises the following steps:
(1) mixing 0.04mol of diphenyl silanediol, 0.08mol of pyridine and 20g of THF in a 250mL single-neck bottle under the protection of nitrogen, and heating to 40 ℃;
(2) a mixture of a defined amount of dimethyldichlorosilane, 20.0g of THF, was added dropwise and the reaction was continued for 6h after the addition was complete.
(3) After most of low boiling point compounds are removed from the reaction mixture through pressure reduction, centrifugation, pressure reduction and other post-treatments, the pyridinium solvent and byproducts are obtained, and the hydroxyphenyl silicone oil is obtained.
In a preferred embodiment, the mass fraction of hydroxyl groups in the hydroxyphenyl silicone oil is 1 to 10%.
Preferably, the mass fraction of hydroxyl groups in the hydroxyphenyl silicone oil is 6%.
In the application, the method for determining the mass fraction of hydroxyl in the hydroxyphenyl silicone oil comprises the following steps: weighing 1g of hydroxyphenyl silicone oil into a 250mL iodine flask, adding 10.0mL of toluene to dissolve, transferring 25.0mL of 0.5mol/L2, 4-toluene diisocyanate toluene solution and 1mL of 1% catalyst N, N-dimethylcyclohexylamine toluene solution into the toluene solution by a transfer pipette, covering the solution tightly, shaking the solution evenly, and standing the solution for 10 min. Then adding 25.0mL of 1.00mol/L diethylamine toluene solution, covering and shaking up, standing for 10min, adding 20mL of isopropanol and 1-2 drops of bromocresol green indicator solution, and titrating with 0.50mol/L hydrochloric acid standard solution until the blue mutation is yellow. And simultaneously performing a blank test. The mass fraction of hydroxyl groups is calculated as follows:
m(-OH)＝[c×(V1-V0)×17.01]×100/[m×1000]；
wherein m is the mass (g) of the hydroxyphenyl silicone oil;
c is the concentration (mol/L) of the hydrochloric acid standard solution;
V1the volume of hydrochloric acid standard solution (mL) consumed for the sample;
V0the volume of hydrochloric acid standard solution (mL) was consumed for the blank sample.
As a preferable technical scheme, the modified starch, the monoglyceride and the silicone oil have the following weight parts:
20-30% of modified starch;
60-70% of monoglyceride;
10-20% of silicone oil.
Preferably, the weight parts of the modified starch, the monoglyceride and the silicone oil are as follows:
25% of modified starch;
65% of monoglyceride;
10% of silicone oil.
The applicant finds that the weather resistance of the chalk is further improved, the toughness is enhanced, the chalk is moistureproof, and the dust generation amount is greatly reduced after the hydroxyphenyl silicone oil is added. Presumably, the reason is that after the hydroxyphenyl silicone oil is added, the hydroxyphenyl silicone oil interacts with active sites in the modified starch, the monoglyceride and the paraffin to form a network structure around the titanium dioxide, and benzene rings in the hydroxyphenyl silicone oil are embedded into the network structure to form a compact and compact protective effect, so that the generation of nascent oxygen on the titanium dioxide is effectively prevented; the formed compact network structure can limit the migration of small molecules, so that the dust-free chalk is kept in an initial state; in addition, the nonpolar groups on the outermost layer block the entrance of water molecules, so that the chalk can write smoothly even in a humid environment, has clear handwriting and is not broken. Particularly, the weight ratio of the modified starch to the monoglyceride to the silicone oil is as follows: 20-30% of modified starch; 60-70% of monoglyceride; when the content of the silicone oil is 10-15%, the effect is optimal. The possible reasons are: either too much or too little of one of the three components will destroy the compactness and morphology of the network structure, resulting in poor results.
The second aspect of the invention provides a preparation method of the dust-free chalk, which at least comprises the following steps:
s1, adding white oil and paraffin into a stirring container in sequence, stirring for 1-2 hours at a rotating speed of 1500-2500 rpm and a temperature of 70-100 ℃;
s2, sequentially adding titanium dioxide and an auxiliary agent into the stirring container in the step S1, stirring for 1.5-2 hours at the rotating speed of 1500-2500 rpm and the temperature of 80-100 ℃;
s3, injecting the mixture obtained in the step S2 into a mold, pressing, cooling, cutting into finished products, and packaging.
The present invention will be specifically described below by way of examples. It should be noted that the following examples are only for illustrating the present invention and should not be construed as limiting the scope of the present invention, and that the insubstantial modifications and adaptations of the present invention by those skilled in the art based on the above disclosure are still within the scope of the present invention.
In addition, the starting materials used are all commercially available, unless otherwise specified.
Examples
In examples and comparative examples, the preparation methods of the oxidized microcrystalline wax and the hydroxyphenyl silicone oil are as follows.
The preparation method of the oxidized microcrystalline wax comprises the following steps:
(1) adding 10g of microcrystalline wax into a reaction kettle, and heating to melt;
(2) adding 50mg of catalyst manganese acetate and 1.2g of auxiliary agent stearic acid, introducing oxygen with the flow rate of 70-80 mL/min, and reacting at 150 ℃ for 2-10 h to obtain the oxidized microcrystalline wax.
The preparation method of the hydroxyphenyl silicone oil comprises the following steps:
(1) mixing 0.04mol of diphenyl silanediol, 0.08mol of pyridine and 20g of THF in a 250mL single-neck bottle under the protection of nitrogen, and heating to 40 ℃;
(2) a mixture of a defined amount of dimethyldichlorosilane, 20.0g of THF, was added dropwise and the reaction was continued for 6h after the addition was complete.
(3) After most of low boiling point compounds are removed from the reaction mixture through pressure reduction, centrifugation, pressure reduction and other post-treatments, the pyridinium solvent and byproducts are obtained, and the hydroxyphenyl silicone oil is obtained.
Example 1
Embodiment 1 provides an environment-friendly nano dust-free chalk, which comprises the following components in parts by weight:
wherein the titanium dioxide is rutile type titanium dioxide, the particle size of the titanium dioxide is 200-260 nm, and the titanium dioxide (model: BR638) is purchased from Hebei Bofeng chemical Co., Ltd;
the white oil (model number: 15#) is purchased from Xinsu grease Co., Ltd in Wuxi city;
the paraffin is oxidized microcrystalline wax, and the acid value of the oxidized microcrystalline wax is 10mg KOH/g;
the auxiliary agent consists of 4 parts of modified starch, 14 parts of monoglyceride and 2 parts of silicone oil;
the modified starch is sodium starch octenyl succinate;
the monoglyceride is palmitic acid glyceride;
the silicone oil is hydroxyphenyl silicone oil, and the mass fraction of hydroxyl in the hydroxyphenyl silicone oil is 1%.
Embodiment 1 provides a method for preparing dust-free chalk, which comprises the following steps:
s1 adding white oil and paraffin into a stirring container in sequence, stirring at a rotation speed of 2000 r/min and a temperature of 80 ℃ for 1 hour.
S2, adding the titanium dioxide and the auxiliary agent into the stirring container of the step S1 in sequence, stirring for 1.5 hours at the rotating speed of 2000 r/min and the temperature of 90 ℃.
S3, injecting the mixture obtained in the step S2 into a mold, pressing, cooling, cutting into finished products, and packaging.
Example 2
Embodiment 2 provides an environment-friendly nano dust-free chalk, which comprises the following components in parts by weight:
wherein the titanium dioxide is rutile type titanium dioxide, the particle size of the titanium dioxide is 200-260 nm, and the titanium dioxide (model: BR638) is purchased from Hebei Bofeng chemical Co., Ltd;
the white oil (model number: 15#) is purchased from Xinsu grease Co., Ltd in Wuxi city;
the paraffin is oxidized microcrystalline wax, and the acid value of the oxidized microcrystalline wax is 10mg KOH/g;
the auxiliary agent consists of 11 parts of modified starch, 38.5 parts of monoglyceride and 5.5 parts of silicone oil;
the modified starch is sodium starch octenyl succinate;
the monoglyceride is palmitic acid glyceride;
the silicone oil is hydroxyphenyl silicone oil, and the mass fraction of hydroxyl in the hydroxyphenyl silicone oil is 1%.
Embodiment 2 provides a method for preparing dust-free chalk, comprising the following steps:
s1 adding white oil and paraffin into a stirring container in sequence, stirring at a rotation speed of 2000 r/min and a temperature of 80 ℃ for 2 hours.
S2, adding the titanium dioxide and the auxiliary agent into the stirring container of the step S1 in sequence, stirring for 2 hours at the rotating speed of 2000 r/min and the temperature of 90 ℃.
S3, injecting the mixture obtained in the step S2 into a mold, pressing, cooling, cutting into finished products, and packaging.
Example 3
Embodiment 3 provides an environment-friendly nano dust-free chalk, which comprises the following components in parts by weight:
wherein the titanium dioxide is rutile type titanium dioxide, the particle size of the titanium dioxide is 200-260 nm, and the titanium dioxide (model: BR638) is purchased from Hebei Bofeng chemical Co., Ltd;
the white oil (model number: 15#) is purchased from Xinsu grease Co., Ltd in Wuxi city;
the paraffin is oxidized microcrystalline wax, and the acid value of the oxidized microcrystalline wax is 10mg KOH/g;
the auxiliary agent consists of 8 parts of modified starch, 28 parts of monoglyceride and 4 parts of silicone oil;
the modified starch is sodium starch octenyl succinate;
the monoglyceride is palmitic acid glyceride;
the silicone oil is hydroxyphenyl silicone oil, and the mass fraction of hydroxyl in the hydroxyphenyl silicone oil is 1%.
Embodiment 3 provides a method for preparing dust-free chalk, comprising the following steps:
s1 adding white oil and paraffin into a stirring container in sequence, stirring at a rotation speed of 2000 r/min and a temperature of 80 ℃ for 1 hour.
S2, adding the titanium dioxide and the auxiliary agent into the stirring container of the step S1 in sequence, stirring for 1.5 hours at the rotating speed of 2000 r/min and the temperature of 90 ℃.
S3, injecting the mixture obtained in the step S2 into a mold, pressing, cooling, cutting into finished products, and packaging.
Example 4
Embodiment 4 provides an environment-friendly nano dust-free chalk, which comprises the following components in parts by weight:
wherein the titanium dioxide is rutile type titanium dioxide, the particle size of the titanium dioxide is 200-260 nm, and the titanium dioxide (model: BR638) is purchased from Hebei Bofeng chemical Co., Ltd;
the white oil (model number: 15#) is purchased from Xinsu grease Co., Ltd in Wuxi city;
the paraffin is oxidized microcrystalline wax, and the acid value of the oxidized microcrystalline wax is 10mg KOH/g;
the auxiliary agent consists of 12 parts of modified starch, 24 parts of monoglyceride and 4 parts of silicone oil;
the modified starch is sodium starch octenyl succinate;
the monoglyceride is palmitic acid glyceride;
the silicone oil is hydroxyphenyl silicone oil, and the mass fraction of hydroxyl in the hydroxyphenyl silicone oil is 1%.
Example 4 provides a method for preparing dust-free chalk, which comprises the same steps as example 3.
Example 5
Embodiment 5 provides an environment-friendly nano dust-free chalk, which comprises the following components in parts by weight:
wherein the titanium dioxide is rutile type titanium dioxide, the particle size of the titanium dioxide is 200-260 nm, and the titanium dioxide (model: BR638) is purchased from Hebei Bofeng chemical Co., Ltd;
the white oil (model number: 15#) is purchased from Xinsu grease Co., Ltd in Wuxi city;
the paraffin is oxidized microcrystalline wax, and the acid value of the oxidized microcrystalline wax is 10mg KOH/g;
the auxiliary agent consists of 8 parts of modified starch, 24 parts of monoglyceride and 8 parts of silicone oil;
the modified starch is sodium starch octenyl succinate;
the monoglyceride is palmitic acid glyceride;
the silicone oil is hydroxyphenyl silicone oil, and the mass fraction of hydroxyl in the hydroxyphenyl silicone oil is 1%.
Example 5 provides a method for preparing dust-free chalk, which comprises the same steps as example 3.
Example 6
Embodiment 6 provides an environment-friendly nano dust-free chalk, which comprises the following components in parts by weight:
wherein the titanium dioxide is rutile type titanium dioxide, the particle size of the titanium dioxide is 200-260 nm, and the titanium dioxide (model: BR638) is purchased from Hebei Bofeng chemical Co., Ltd;
the white oil (model number: 15#) is purchased from Xinsu grease Co., Ltd in Wuxi city;
the paraffin is oxidized microcrystalline wax, and the acid value of the oxidized microcrystalline wax is 10mg KOH/g;
the auxiliary agent consists of 10 parts of modified starch, 26 parts of monoglyceride and 4 parts of silicone oil;
the modified starch is sodium starch octenyl succinate;
the monoglyceride is palmitic acid glyceride;
the silicone oil is hydroxyphenyl silicone oil, and the mass fraction of hydroxyl in the hydroxyphenyl silicone oil is 1%.
Example 6 provides a method for preparing dust-free chalk, which comprises the same steps as example 3.
Example 7
Embodiment 7 provides an environment-friendly nano dust-free chalk, which comprises the following specific components in parts by weight as in embodiment 6, and is characterized in that the mass fraction of hydroxyl in the hydroxyphenyl silicone oil is 10%.
Example 7 provides a method for preparing dust-free chalk, which comprises the same steps as example 3.
Example 8
Embodiment 8 provides an environment-friendly nano dust-free chalk, which comprises the following specific components in parts by weight as in embodiment 6, and is different from that in the hydroxyphenyl silicone oil, the mass fraction of hydroxyl groups is 6%.
Example 8 provides a method for preparing dust-free chalk, which comprises the same steps as example 3.
Comparative example 1
Comparative example 1 provides an environment-friendly nano dust-free chalk, the specific components and the weight parts are the same as those of example 8, and the difference is that the titanium dioxide is anatase titanium dioxide.
Comparative example 1 provides a method for preparing dust-free chalk, which comprises the same steps as example 3.
Comparative example 2
Comparative example 2 provides an environment-friendly nano dust-free chalk, which comprises the same specific components and weight parts as example 8, and is different from the paraffin wax which is non-oxidized microcrystalline wax.
Comparative example 2 provides a method for preparing dust-free chalk, which comprises the same steps as example 3.
Comparative example 3
Comparative example 3 provides an environment-friendly nano dust-free chalk, which comprises the same specific components and parts by weight as example 8, and is different in that the auxiliary agent consists of 26 parts of monoglyceride and 14 parts of silicone oil.
Comparative example 3 provides a method for preparing dust-free chalk, which comprises the same steps as example 3.
Comparative example 4
Comparative example 4 provides an environment-friendly nano dust-free chalk, which comprises the same specific components and parts by weight as example 8, and is different in that the auxiliary agent consists of 28 parts of modified starch and 12 parts of silicone oil.
Comparative example 4 provides a method for preparing dust-free chalk, which comprises the same steps as example 3.
Comparative example 5
Comparative example 5 provides an environment-friendly nano dust-free chalk, which has the same specific components and weight parts as example 8, and is different in that the silicone oil is methyl silicone oil.
Comparative example 5 provides a method for preparing dust-free chalk, which comprises the same steps as example 3.
Comparative example 6
Comparative example 6 provides an environment-friendly nano dust-free chalk, which has the same specific components and weight parts as example 8, and is different from the above-mentioned silicone oil in that the silicone oil is hydroxy amino silicone oil.
The preparation method of the hydroxyl amino silicone oil comprises the following steps:
(1) mixing 0.04mol of 3-aminopropyltrihydroxysilane, 0.08mol of pyridine and 20g of THF in a 250mL single-neck bottle under the protection of nitrogen, and heating to 40 ℃;
(2) a mixture of 0.03mol of dimethyldichlorosilane and 20.0g of THF is added dropwise and the reaction is continued for 6h after the addition is complete.
(3) After most of low boiling point compounds are removed from the reaction mixture through pressure reduction, centrifugation, pressure reduction and other post-treatments, the pyridinium solvent and byproducts are obtained, and the hydroxyl amino silicone oil is obtained.
Comparative example 6 provides a method for preparing a dust-free chalk, which comprises the same steps as example 3.
Comparative example 7
Comparative example 7 provides an environment-friendly nano dust-free chalk, which comprises the same specific components and weight parts as example 8, except that the hydroxy phenyl silicone oil contains 0.2% of hydroxy.
Comparative example 7 provides a method for preparing a dust-free chalk, which comprises the same steps as example 3.
Comparative example 8
Comparative example 8 provides an environment-friendly nano dust-free chalk, which comprises the same specific components and weight parts as example 8, and is different from example 8 in that the hydroxy phenyl silicone oil contains 20% of hydroxy.
Comparative example 8 provides a method for preparing a dust-free chalk, which comprises the same steps as example 3.
Performance testing
The dust-free chalks described in examples 1 to 8 and comparative examples 1 to 8 were subjected to a performance test.
And (3) fracture resistance test: fixing the chalk in the position 1cm away from the two ends, hanging the plastic bag in the air by using a line rope without elasticity in the middle position of the chalk length, adding nails with the length of 30mm into the bag until the chalk is broken, and counting the added nails. A total of 10 chalks were tested and then averaged. Unit: and (4) root.
Moisture absorption test: the chalk was left to stand in a container having a relative humidity of 50% for a period of 20 days, and then the percentage of weight increase before and after the standing was measured. A total of 10 chalks were tested and then averaged. Unit: % of the total weight of the composition.
And (3) testing the folding resistance after moisture absorption: the chalk was left in a container having a relative humidity of 50% for a period of 20 days and then tested for breaking resistance after moisture absorption according to the method for breaking resistance test described above. Unit: and (4) root.
Measuring the amount of generated dust: a paper groove which is 5cm wide and 3cm deep is arranged at a position which is about 2cm away from the bottom of a blackboard with the length of 2.5mm and is level with the bottom of the blackboard, the blackboard is divided into squares with the length of 4cm X4 cm, ancient poems 'quiet night thought' is written for five times, the sizes of the fonts are as full as possible, the test is completed by the same person, and each time one piece of chalk is tested, the chalk is rested for 10 minutes, and dust in the paper groove is collected and weighed. A total of 10 chalks were tested and then averaged. Unit: and (5) mg.
TABLE 1 test results of the dust-free chalk performance described in examples 1-8 and comparative examples 1-8
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in other forms, and any person skilled in the art may modify or change the technical content of the above disclosure into equivalent embodiments with equivalent changes, but all those simple modifications, equivalent changes and modifications made to the above embodiments according to the technical spirit of the present invention still belong to the protection scope of the present invention.
Claims (5)
1. The environment-friendly nano dust-free chalk is characterized by at least comprising the following components in parts by weight: 50-80 parts of titanium dioxide, 1-15 parts of white oil, 1-12 parts of paraffin and 20-55 parts of auxiliary agent;
wherein the auxiliary agent consists of modified starch, monoglyceride and silicone oil; the modified starch, the monoglyceride and the silicone oil are prepared from the following components in parts by weight: 20-30% of modified starch; 60-70% of monoglyceride; 10-20% of silicone oil;
the modified starch is sodium starch octenyl succinate;
the titanium dioxide is rutile type titanium dioxide;
the paraffin is oxidized microcrystalline paraffin;
the silicone oil is hydroxyphenyl silicone oil, and the mass fraction of hydroxyl in the hydroxyphenyl silicone oil is 1-10%.
2. A dust-free chalk according to claim 1, wherein the particle size of the rutile type titanium dioxide is 50-500 nm.
3. The dustless chalk of claim 1, wherein the monoglyceride is at least one of glyceryl oleate, glyceryl linoleate, glyceryl palmitate, glyceryl behenate, glyceryl stearate, glyceryl laurate and glyceryl linolenate.
4. A chalk in accordance with claim 3, wherein the monoglyceride is glyceryl palmitate.
5. A method for preparing dust-free chalk according to any one of the claims 1 to 4, characterized by comprising at least the following steps:
s1, adding white oil and paraffin into a stirring container in sequence, stirring for 1-2 hours at a rotating speed of 1500-2500 rpm and a temperature of 70-100 ℃;
s2, sequentially adding titanium dioxide and an auxiliary agent into the stirring container in the step S1, stirring for 1.5-2 hours at the rotating speed of 1500-2500 rpm and the temperature of 80-100 ℃;
s3, injecting the mixture obtained in the step S2 into a mold, pressing, cooling, cutting into finished products, and packaging.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2011143037A1 (en) * | 2010-05-12 | 2011-11-17 | Elevance Renewable Sciences, Inc. | Natural oil based marking compositions and their methods of making |
| CN102898898A (en) * | 2012-10-11 | 2013-01-30 | 宁波杭州湾新区第九区科技服务有限公司 | Dust-free environment-friendly chalk and preparation method thereof |
| CN104275963A (en) * | 2013-07-09 | 2015-01-14 | 修森经贸发展(上海)有限公司 | Environment-friendly scrawling bar for children |
| CN105505000A (en) * | 2014-10-14 | 2016-04-20 | 天长市地震办公室 | Dustless chalk and manufacturing method thereof |
| EP3272819A1 (en) * | 2016-07-20 | 2018-01-24 | Faber- Castell AG | Refill, chalk or colour tablet for writing, painting and/or cosmetic purposes, stick with a refill and method for producing a refill, chalk or colour tablet |
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- 2019-02-25 CN CN201910138604.5A patent/CN109943151B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011143037A1 (en) * | 2010-05-12 | 2011-11-17 | Elevance Renewable Sciences, Inc. | Natural oil based marking compositions and their methods of making |
| CN102898898A (en) * | 2012-10-11 | 2013-01-30 | 宁波杭州湾新区第九区科技服务有限公司 | Dust-free environment-friendly chalk and preparation method thereof |
| CN104275963A (en) * | 2013-07-09 | 2015-01-14 | 修森经贸发展(上海)有限公司 | Environment-friendly scrawling bar for children |
| CN105505000A (en) * | 2014-10-14 | 2016-04-20 | 天长市地震办公室 | Dustless chalk and manufacturing method thereof |
| EP3272819A1 (en) * | 2016-07-20 | 2018-01-24 | Faber- Castell AG | Refill, chalk or colour tablet for writing, painting and/or cosmetic purposes, stick with a refill and method for producing a refill, chalk or colour tablet |
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