Study on the Antibacterial and Deodorization Effect of 4,4-Dichloro-2-Hydroxydiphenyl Ether in Laundry Gel Beads

Huang Qing,Sun Lianlian,Gezan,Fang Lingdan

Zanyu Technology Group Co.,Ltd.,China

Abstract In the formulation development of laundry gel beads,4,4-dichloro-2-hydroxydiphenyl ether (HP-100) was used as a bacteriostatic agent,and the effect of HP-100 dosage on the bacteriostatic rate of laundry gel bead samples with different formulation systems was examined by the suspension quantification method;the long-lasting bacteriostatic performance of laundry gel bead samples added with HP-100 was investigated by the absorption method for evaluating the antimicrobial performance of textiles;the effect of HP-100 on the odor control of laundry gel bead samples was investigated by filling out surveys and questionnaires using the actual measurement method.Questionnaire was used to investigate the effect of HP-100 on odor control.The test results showed that the antibacterial rate of the two laundry gel samples against S.aureus increased with the increase of HP-100 dosage,and the antibacterial rate of Formula 1 reached 99.9% when the dosage of HP-100 was 0.3%;the antibacterial rate of cotton cloth washed with the laundry gel sample of Formula 1+0.3%HP-100 was more than 50% after 24 h,and still had the antibacterial effect;the antibacterial rate of cotton cloth washed with the sample of laundry gel with HP-100 was more than 50% after 24 h,and still had the antibacterial effect;the antibacterial effect of the sample with HP-100 was more than 50% after 24 h,and still had the antibacterial effect.The fabrics washed with HP-100 added laundry gel beads had better odor control than those treated with laundry gel beads without HP-100,and the addition of HP-100 to laundry gel beads could have antibacterial and deodorizing effects.

Key words laundry gel;HP-100;long-lasting anti-bacterial;odor control

Compared with traditional laundry detergents,laundry gel beads have higher content of actives and better decontamination effect,which is a new type of concentrated liquid detergent[1-3].In recent years,with the impact of the epidemic and the rise of the new generation of consumers,consumer demand for laundry cleaning products is no longer satisfied with the basic function of stain removal and cleaning,but also requires antibacterial and scent retention efficacy at the same time.In order to meet the market demand,the formulation developers choose suitable antibacterial agents to develop a laundry gel product with antibacterial effect,which can realize the effective removal of harmful bacteria and viruses on the clothes while cleaning the clothes to protect the health of consumers,and has better practical significance[4-6].

There are many types of antibacterial agents for laundry detergents,among which 4,4-Dichloro-2-Hydroxydiphenyl Ether (HP-100) is a safe and efficient broad-spectrum antimicrobial agent.HP-100 not only kills bacteria,but also inhibits the re-growth of a small number of bacteria,with long-lasting anti-bacterial effect,and can also effectively inhibit the odor caused by microbial growth.It is suitable for use in household clothing cleaning and care products,kitchen cleaning products and hard surface cleaning products[7,8].Since HP-100 has one less chlorine atom than triclosan,itis less irritating to the human body,and thus is more widely used,and is an iteration of triclosan[9-11].

In this study,the antibacterial performance of HP-100 in different laundry gel systems wasinvestigated by using HP-100 as an antibacterial agent,and the effects of the dosage of HP-100 on the antibacterial rate of laundry gel were investigated,as well as the long-lasting antibacterial effect of HP-100in laundry gel.The effect of HP-100 on the control of fabric odor was investigated through practical evaluation,which is expected to provide certain reference data for the development of new products of antibacterial and deodorizing laundry gels.

1 Experimental

1.1 Materials and instruments

Straight-chain alkyl benzene sulfonic acid (LAS,96% by mass),fatty alcohol polyoxyethylene ether sodium sulfate (AES,70% by mass),industrial grade,Jiaxing Zanyu Science and Technology Co.,Ltd;4,4-Dichloro-2-hydroxydiphenyl ether (HP-100),industrial grade,BASF;1,2-Propanediol,analytically pure,Aladdin Reagent;Trisodium citrate,analytically pure,Shanghai Lingfeng Chemical Reagent Co.,Ltd.;Liquid alkaline protease,industrial grade,Novozymes Biotechnology Co.,Ltd;Staphyloccocus aureus,model ATCC 6538,China General Microbial Strain Preservation and Management Center;Strain medium,Beijing Aoboxing Biotechnology Co.,Ltd.

HWS-12 electrothermal constant temperature water bath,Shanghai Yiheng Scientific Instrument Co.,Ltd;ST3100 laboratory pH meter,OHAUS Instruments (Changzhou) Co.,Ltd;RHLQ-III vertical decontamination machine,China Research Institute of Daily-use Chemical Industry.

1.2 Experimental methods

1.2.1 Preparation of laundry gel samples

According to the formulation of laundry gel beads in Table 1,weigh a certain amount of water,propylene glycol,AEO9,triethanolamine,fatty acids,LAS in a beaker,stirring at 40 ℃,300 rad/s speed,until the reaction is complete,use a pH meter to test the pH of 1% aqueous solution,when the pH>7.0,indicating that sulfonic acid and fatty acids have been completely neutralized,and then slowly add AES,HP-100 stirring until completely dissolved,and then add AES,HP-100 to test the product pH.Test the pH value of the product Modulate the pH of the product with acid-base regulator to make the pH of the laundry gel beads at 8.0～9.0.Reduce the pH to room temperature,add enzyme,flavor,pigment and distilled water,and stir well to get the sample of laundry gel beads.

Considering that the addition of different levels of HP-100 in different surfactant formulations will have a certain effect on the bacterial inhibition rate of laundry gel beads,two groups of different basic formulations of laundry gel beads were formulated,with formulation 1 based on anionic surfactant,and formulation 2 based on nonionic surfactant,and the content of the rest of the components was the same.The specific formulations of the laundry gel are shown in Table 1.

Table 1. Laundry bead recipe

1.2.2 Determination of anti-bacterial properties of laundry gel

Referring to QB/T 2738-2012 Evaluation Methods of Antibacterial and Inhibitory Effects of Daily Chemical Products and QB/T 2850-2007 Industry Standard Tests of Antibacterial and Inhibitory Detergents,the test strains were chosen from Staphylococcus aureus (Staphylococcus aureus) of the Chinese Center for Preservation and Management of Ordinary Microbial Strains (CCMS),model ATCC 6538.

Strain activation: Staphylococcus aureus wasinoculated in a flat dish and incubated at 37 ℃ for 24 hin a constant temperature incubator,and activated and passed on for two times,i.e.,the third generation of cultures,and the whole process was carried out under aseptic operation.

Preparation of bacterial solution: take the activated bacteria with an inoculating ring and dissolve it in phosphate buffer solution (PBS),detectit with a turbidimeter until the value is 0.5,at this time,the number of recovered colonies is about 1×108～9×108CFU/mL,and dilute it with PBS buffer 2 times until the number of recovered colonies is about 1×106CFU/mL～9×106CFU/mL.

Steps of bacterial inhibition: dilute the experimental samples with sterile standard hard water to the specified concentration;take 5 mL of the sample dilution into a sterilized test tube,constant temperature at 20 ℃ for 5 min;take 0.1 mL of bacterial suspension and add it into a test tube containing 5 mL of sample dilution,mix well and leave it for 15 min;take 0.5 mL of the mixture of bacteria and sample and add it into a test tube containing 4.5 mL of LPBS buffer,mix well and leave it for 10 min,and then repeat the procedure.Repeat the above operation,the strain and sample mixture was diluted for 2 times,and finally 1 mL was sucked from each of the 2 times of mixed dilution,placed in a sterilized petri dish,each mixed dilution was inoculated with 2 sterilized petri dishes;inoculated in nutrient agar medium by decantation method,and incubated at 37 ℃ for 48 h,to do the calculation of the number of viable bacteria;replace the experimental samples by PBS,and at the same time,operate according to the above steps,and calculate the bacterial inhibition rate as the control samples.The experiment was repeated 3 times to find the average value.

1.2.3 Measurement of long-lasting antibacterial properties

Referring to AATCC 100 antimicrobial textile assessment method and GB/T20944.2 textile antimicrobial performance assessment,the strain Staphylococcus aureus was selected.

Bacterial solution preparation: after activation of the strain,take typical colonies and dilute them with diluent,and detect them with turbidimeter,until the corresponding concentration of live bacteria is 1×105～3×105CFU/mL,as the test bacterial solution.

Sample preparation: Prepare several pieces of cotton fabrics of appropriate size and wash them according to the test conditions in GB/T 12490-1990,in which test sample 1 was washed with laundry gel beads containing bacteriostatic agent,sample 2 was washed with laundry gel beads without bacteriostatic agent (the rest of the ingredients were the same),and the control sample was washed with hard water.The test samples and control samples were placed in glass vials and sterilized by autoclave sterilization (121 ℃,103 KPa,15 min).

Bacteriostatic procedures: take the test bacterial solution dispersed inoculation in each vial on the specimen;a batch of control samples to add the elution medium to elute immediately;another batch of control samples in the inoculation of bacterial solution at 37 ℃ after the incubation for 24 h;the rest of the inoculation of the test bacterial solution at 37 ℃ after the cultivation of 0 h,1 h,6 h,18 h,24 h (respectively,set up the control group);after the cultivation of vials with the elution of the medium,the bacteria will be washed down;For each eluate,two 10-fold dilution series were made respectively;1 mL from each dilution series was injected into the petri dish,nutrient agar medium was added,two petridishes were made for one dilution,and the culture was incubated at 37 ℃ for 48 h for the calculation of the number of viable bacteria.The experiment was repeated 3 times for the mean value.

1.2.4 Odor control evaluation

For the evaluation of odors,the actual assessment was taken by filling out a questionnaire.Test population: by 10 trained,more sensitive to the odor of the composition of the personnel,including 4 boys,6 girls,age 20～ <40 years old.

Specific experiments: take 4 pieces of the same white towels,numbered 1～ 4,respectively,with laundry gel beads to be tested samples were cleaned and placed in a dark and humid space to dry,simulating the actual clothes drying in cloudy and rainy weather;after drying,take the 4 pieces of towels to the test personnel to evaluate the blind samples,fill out the questionnaire,the questionnaire according to the cognition of each person to the odor,from 1 point to 7 points for scoring.Where: 1 point means no odor,7 points means a strong odor,and finally the ratings of the testers on each towel were counted and the average score of each towel was calculated,with a low score indicating the smaller the odor of the towel,and a high score indicating the higher the odor of the towel.

2 Results and discussion

2.1 Effect of HP-100 dosage on the antibacterial rate of laundry gel beads

According to the preparation method of laundry gel samples,a series of laundry gel samples with different HP-100 dosage were obtained,and the antibacterial rate of the samples was tested with reference to the test method of bacterial inhibition ratein 1.2.2,and the results of the test are shown in Table 2.It can be seen in Table 2,as the dosage of HP-100increases,the antibacterial rate of laundry gel shows an increasing trend,and the inhibitory rate of laundry gel reached 99.9% when the dosage of HP-100 in formula 1 was 0.3%;and it is presumed that the high content of non-ionic surface activity in formula 2is probably responsible for the high inhibitory rate of formula 2.In formulation 1,the antibacterial rate of laundry gel reached 99.9% at 0.3% of HP-100 dosage;in formulation 2,the antibacterial rate of laundry gel reached 99.9% at 0.5% of HP-100 dosage,and it was speculated that the high content of nonionic epitopes in formulation 2 might affect the antibacterial effect of HP-100[12].Considering the long-lasting bacterial inhibition experiment and the odor control experiment,the dosage of formulation 1+0.3% HP-100 was selected.

Table 2.Effect of HP-100 content on bacteriostatic properties of laundry beads

2.2 Evaluation of long-lasting antibacterial effect

HP-100 can be deposited on the surface of fabric fibers,and then slowly and persistently exert its antibacterial effect.In order to further investigate the long-lasting antibacterial effect of HP-100,on the basis of formula 1,the amount of HP-100 was 0.3%,and the cotton fabric sample 1 was washed with the above antibacterial laundry gel beads,cotton fabric sample 2 was washed with laundry gel beads without antibacterial agent(the rest of the ingredients were the same),and the control sample was washed with hard water,and the antibacterial effect of the antibacterial agent was investigated in the contact time with Staphylococcus aureus,respectively 0 h,1 h,6 h,18 h,and 24 h.The results are shown in Table 3.1 h,6 h,18 h and 24 h,and the results are shown in Table 3.As can be seen from Table 3,with the increase of time,the inhibition rate of test sample 1 gradually decreased,but the inhibition rate of 24 h after washing was 53.4%,which still had the inhibition effect;the inhibition rate of test sample 2 also gradually decreased,but the inhibition rate of 24 h after washing was 18.9%,which did not have the inhibition effect.

Table 3.Tests for long-acting bacteriostatic properties

2.3 Evaluation of odor control effect

According to 1.2.4 measurement method,10 questionnaires were returned,and the 10 questionnaires were counted and summarized (see Table 4 for details).The results show that: the average scores of Towel 1 and Towel 2 are 2.7 and 3.2,and the average scores of Towel 3 and Towel 4 are 5.3 and 5.4;the average scores of Towel 1 and Towel 2 are lower than those of Towel 3 and Towel 4,which indicates that the odor of Towel 1 and Towel 2 is superior to that of Towel 3 and Towel 4;Towel 1 and Towel 2 are the towels washed with the addition of laundry gel beads of 0.3% HP-100,and Towel 3 and Towel 4 are towels washed with control laundry gel beads samples.Towel 3 and Towel 4 were towels that were cleaned with a control laundry gel bead sample,further indicating that HP-100 is effective in controlling odor.

Table 4.Odor control assessment

3 Summary

In the formulation system 1 of laundry gel with anionic surfactant as the main agent,when the dosage of HP-100 was 0.3% and the contact time was 15 min,the inhibition rate of Staphylococcus aureus reached 99.9%,and the laundry gel had a betterinhibition of Staphylococcus aureus;fabrics treated with bacteriostatic laundry gel had an inhibition rate of ≥50% after 24 h of contact with Staphylococcus aureus,indicating that it still had a better inhibition effect;through the crowd experiment,it was known that the addition of HP-100 could effectively inhibit the odor problem caused by microorganisms breeding.50% after 24 h contact with S.aureus,indicating that it still has a good effect of bacterial inhibition;through the crowd experiment,it can be seen that the addition of HP-100 can effectively inhibit the odor problem caused by the growth of microorganisms.In the post epidemic era,the demand for healthy and safe laundry gels continues to increase.We will continue to follow up with more in-depth research.