CN102495059A - Method for measuring acid value of unsaturated polyester resin - Google Patents
Method for measuring acid value of unsaturated polyester resin Download PDFInfo
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- CN102495059A CN102495059A CN2011104095346A CN201110409534A CN102495059A CN 102495059 A CN102495059 A CN 102495059A CN 2011104095346 A CN2011104095346 A CN 2011104095346A CN 201110409534 A CN201110409534 A CN 201110409534A CN 102495059 A CN102495059 A CN 102495059A
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- polyester resin
- unsaturated polyester
- solution
- toluene
- acid value
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Abstract
The invention discloses a method for measuring the acid value of unsaturated polyester resin. The method comprises the following steps of: dissolving a certain quantity of polyester resin in a solvent; by taking phenolphthalein as an indicator, titrating with a potassium hydroxide-ethanol standard solution until the solution turns red; and calculating the acid value according to the consumption of the titrating solution. As the toxic solvent 'toluene' is replaced by an anhydrous acetone solution, the dissolution is fast without heating, and the shortcomings that the toluene has low dissolubility against resin and the dissolution is excessively slow at low temperature are solved; and meanwhile, the toxicity of the anhydrous acetone solution is much lower than that of toluene, and the anhydrous acetone solution is more acceptable to the staff. Moreover, relative to the thymol turning blue from yellow, the colorless phenolphthalein indicator turning red is obvious and easy to observe.
Description
Technical field
The invention belongs to the method for testing field, the concrete assay method of a kind of glass fiber infiltration agent that relate to the vibrin acid number.
Background technology
In the acid value measuring of prior art for the unsaturated polyester resin acid number, the assay method according to GB GB2895-82 carries out usually, and there is following problem in this method:
1, toluene harmfulness.
Adopt " toluene-absolute ethyl alcohol " mixed solvent (2: 1), toluene has following harmfulness:
[health hazard]: suck or eat harmfully, cause central nervous system to suppress. steam possibly cause headache, fatigue, dizzy, dim eyesight, numbness, nauseating, confusion, exercise not harmony, eats or possibly cause that suck-back goes into lung when vomitting.Neurasthenic syndrome can take place, hepatomegaly, woman worker's menoxenia etc. in long-term contact.Dry skin, chap, dermatitis.
[environmental impact]: do not have tangible biological concentration, tool biodegradability.Be released in soil and the water, can volatilize and carry out biolysis, be released in the air, can and decay with the hydroxyl free radical reaction.
[physical property and chemical hazard]: its steam and liquid are inflammable, liquid meeting stored charge, and the steam lta can be transmitted at a distance, meets burning things which may cause a fire disaster and possibly cause tempering.High temperature can decompose generation poison gas, and the container in the scorching field may break, explode.
2, test speed is slow.
In the process of the synthetic unsaturated polyester resin of reality, require the acid number of resin to control within the specific limits, in post-synthesis phase, operate through frequent acid value measuring and guarantee resin index up to specification.If test speed is slow, measure the result and lag behind, can not the actual response degree, produce just control bad, so it is just very important to improve test speed." toluene-ethanol " is poor to resin dissolves property, and melting speed is slow.Particularly temperature low winter, insoluble particles often occurs, even need heating just can dissolve, could titration after the solution after the heating need cool off, very consuming time, the test duration surpasses 40 minutes, influences test result.
3, observe inconvenience
Select for use " thymol blue " to make indicator in the GB, two kinds of color change intervals are arranged: (1) acid range is pH1.2～2.8, by red flavescence look; (2) the alkali scope is a pH value 8.0～9.6, and is blue by xanthochromia.Select the alkaline range variable color in the standard for use.Color is blue by xanthochromia, changes not obviously during to equivalent point, is unfavorable for observing.And phenolphthalein is by the colourless redness that becomes, and the Temin shows, and is easy to observe.
Summary of the invention
For addressing the above problem, the present invention provides a kind of assay method of unsaturated polyester resin acid number.
A kind of assay method of unsaturated polyester resin acid number is characterized in that vibrin is dissolved in the anhydrous propanone solvent, cooperates indicator to carry out titration with aqueous slkali, goes out acid number according to the consumption calculating of vs.
Said anhydrous propanone water cut is lower than 0.1%.
Said indicator is a phenolphthalein.
Said aqueous slkali is the KOH ethanolic solution.
Technique effect:
Test philosophy of the present invention is following:
Residual acid or anhydride reaction in KOH and the vibrin utilizes the KOH volume that consumes, and calculates KOH milligram number that (unreacted) acid free in the 1g resin is consumed.Acid number is low more, explains that pet reaction is complete more.
KOH+R-CO-OH → R-CO-OK+H
2O, indicator reaches titration end-point in little variable color when excessive of aqueous slkali.
The present invention adopts anhydrous propanone solution replacement toxic solvent " toluene ", and melting speed fast (general 2～5 minutes) need not heat, and it is poor to resin dissolves property to have solved toluene, and the slow excessively shortcoming of dissolution velocity can realize quick dissolving when temperature was low, raised the efficiency; Its toxicity is far below toluene simultaneously, and acetone does not have special toxicity to human body, because its toxicity is low, the metabolism detoxifcation is fast, and acute poisoning is comparatively rare under the working condition.Also can reduce employee's occupational hazards, employee's degree of recognition is higher.
Phenolphthalein indicator color change interval: 8.2-10.0, color is by the colourless redness that becomes when arriving equivalent point.Is blue with respect to the thymol blue color by xanthochromia, and phenolphthalein indicator becomes red color clearly by colourless, is easy to observe.
Embodiment
The present invention is further explained the present invention in order better to explain below in conjunction with embodiment.
Embodiment 1
1. reagent
Potassium hydroxide (analyzing pure), absolute ethyl alcohol, oxalic acid (analyzing pure), acetone (moisture be lower than 0.1%), phenolphthalein (0.5%), distilled water.
2. instrument
Beaker (200ml); Glass bar; Volumetric flask (500ml); 3 of conical flasks (250ml); Base buret (25ml, scale division value 0.01ml);
Electronic scale (hundredths, very much the position each one).
3. solution preparation
3.1 0.5% phenolphthalein solution (indicator) preparation
5g phenolphthalein is dissolved in the absolute ethyl alcohol, is made into 1L solution.
3.2 the preparation of 0.1mol/L potassium hydroxide-ethanol solution
Weighing: with very much the position electronic scale claim about 3.5g potassium hydroxide, place the beaker of 250ml;
Dissolving: pour in the beaker with about 150ml absolute ethyl alcohol, stir with glass bar then, make potassium hydroxide dissolve (, can add an absolute ethyl alcohol) fully if solute effect is bad;
Move appearance: will dissolve good potassium hydroxide solution and move in the 500ml volumetric flask; All the other are added absolute ethyl alcohol and are settled to 500ml, shake up repeatedly.
Demarcate: take by weighing 3 parts of oxalic acid, every part of m gram (approximately 0.1g) places conical flask respectively, respectively adds the 50ml dissolved in distilled water.Add 5 0.5% phenolphthalein solutions and make indicator, to red, volume is Vml with the potassium hydroxide-ethanol titration of newly joining.
Concentration C (mol/L) is calculated: m/ (63.035v), get the mean value of three appearance, unit: mol/L.
4, acid number (Av) is measured
Take by weighing two parts of unsaturated polyester resins, and every part of m gram (about 1～3g), add in the conical flask, respectively add 50ml acetone, shake to sample and dissolve fully.Dissolving fully adds 5 instructions phenolphthalein solutions then, does not disappear and is terminal point with the 0.1mol/L potassium hydroxide-ethanol solution titration 20s that takes on a red color, and writing down the titration volume is V;
Get 50ml acetone, the same blank titration, recording volume is V
0
Calculate
A
V-acid number result, the mgKOH/g of unit resin.
The volumetric molar concentration of C-potassium hydroxide standard solution, mol/l
The potassium hydroxide standard solution volume that V-titration sample consumes, ml;
V
0The potassium hydroxide standard solution volume that-titration blank test consumes, ml;
The quality of m-sample, g.
5. the result representes
At least survey 2 samples, sample mean, result are got a decimal.
In the test process, the acetone soln of solvent resin becomes the white opacity shape in the conical flask if observe, and then explanation wherein is mixed with water.Need to confirm whether contain moisture in dry conical flask, KOH standard solution, the acetone again, thereby avoid moisture to bring into.
In the practical application, produce with this method test acid number, control, test is fast, and consistent with the GB-2895-82 test result, effect is very good.
Should be understood that; The above embodiment can make those skilled in the art more fully understand the invention; But do not limit the present invention in any way creation; All do not break away from the technical scheme and the improvement thereof of the spirit and the scope of the invention, the for example concentration of each reagent and weighing apparatus etc., and it all is encompassed in the middle of the protection domain of the invention patent.
Claims (4)
1. the assay method of a unsaturated polyester resin acid number is characterized in that may further comprise the steps: vibrin is dissolved in the anhydrous propanone solvent, cooperates indicator to carry out titration with aqueous slkali, go out acid number according to the consumption calculating of vs.
2. the assay method of a kind of unsaturated polyester resin acid number according to claim 1 is characterized in that said anhydrous propanone water cut is lower than 0.1%.
3. the assay method of a kind of unsaturated polyester resin acid number according to claim 1 is characterized in that said indicator is a phenolphthalein.
4. the assay method of a kind of unsaturated polyester resin acid number according to claim 1 is characterized in that said aqueous slkali is the KOH ethanolic solution.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011104095346A CN102495059A (en) | 2011-12-09 | 2011-12-09 | Method for measuring acid value of unsaturated polyester resin |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011104095346A CN102495059A (en) | 2011-12-09 | 2011-12-09 | Method for measuring acid value of unsaturated polyester resin |
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| CN102495059A true CN102495059A (en) | 2012-06-13 |
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| CN2011104095346A Pending CN102495059A (en) | 2011-12-09 | 2011-12-09 | Method for measuring acid value of unsaturated polyester resin |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105891410A (en) * | 2016-04-14 | 2016-08-24 | 梧州市产品质量检验所 | Detection method of abietic acid in rosin |
| CN106324185B (en) * | 2016-08-26 | 2018-11-02 | 巨石集团有限公司 | A kind of assay method of Emulsion of UPR acid value |
| CN113607877A (en) * | 2021-07-27 | 2021-11-05 | 威海拓展纤维有限公司 | Method for testing acid value of water-soluble resin |
Citations (2)
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| CN1712943A (en) * | 2005-06-09 | 2005-12-28 | 武汉化工学院 | Determination of epoxide number |
| CN102135500A (en) * | 2010-01-22 | 2011-07-27 | 财团法人工业技术研究院 | Reagent and method for detecting melamine |
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2011
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1712943A (en) * | 2005-06-09 | 2005-12-28 | 武汉化工学院 | Determination of epoxide number |
| CN102135500A (en) * | 2010-01-22 | 2011-07-27 | 财团法人工业技术研究院 | Reagent and method for detecting melamine |
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| 《聚氨酯工业》 19940515 徐妙玲 聚酯多元醇中酸值的测定 , * |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105891410A (en) * | 2016-04-14 | 2016-08-24 | 梧州市产品质量检验所 | Detection method of abietic acid in rosin |
| CN106324185B (en) * | 2016-08-26 | 2018-11-02 | 巨石集团有限公司 | A kind of assay method of Emulsion of UPR acid value |
| CN113607877A (en) * | 2021-07-27 | 2021-11-05 | 威海拓展纤维有限公司 | Method for testing acid value of water-soluble resin |
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Application publication date: 20120613 |