A structural hair perm product, a method for preparing the same, and a softener composition

Abstract

The application discloses a structure-protected perm product, a preparation method thereof and a softener composition. The perm product is human curly hair treated by a perm process, wherein the Raman peak intensity of the amide III band (1200-1300 cm ‑1 ) in the keratin of the perm product is not less than 90% of that of a homologous untreated control hair after normalization of the phenylalanine ring breathing peak (1003 cm ‑1 ); and meanwhile, the following conditions are met: the radial distribution coefficient of disulfide bond is less than 15%, the retention rate of 18-MEA is not less than 80%, the DSC alpha-helix characteristic peak exists, and the absolute values of the change rates of the peak temperature and the peak area relative to the control are both less than or equal to 15%, and the content of cysteic acid is less than 0.5 mol / kg. The above product is realized by a synergistic process of a softener containing a DMI and an oleic acid penetration carrier at pH 6.0-7.0, combined with 80-90 DEG C medium-temperature heating and rapid cooling within 120 seconds after heating. The application overcomes the technical prejudice that "perming must damage the protein main chain".

Description

Technical Field

[0001] This invention relates to the field of hair care technology, specifically to a perming product that maintains a high level of keratin backbone (peptide bond) integrity while achieving a lasting curl, as well as a softening agent composition and preparation method for preparing the product. Background Technology

[0002] Traditional perming (especially hot perming) typically uses strongly alkaline (pH > 8.5) reducing softening agents combined with high-temperature treatments above 100°C to achieve lasting curls. While breaking disulfide bonds, this process inevitably catalyzes the hydrolysis and breakage of peptide bonds in the keratin backbone, damaging the hair's basic structure. Furthermore, the high temperature causes irreversible thermal denaturation of the α-helix of keratin, resulting in the loss of its natural water-retention capacity and mechanical properties.

[0003] While existing low-pH perming techniques use mild reducing agents such as pH 6.0-8.0 or cysteine, the inventors found through comparative experiments that the intensity of the amide III band peak still significantly decreased after such treatment (by approximately 18-25%), indicating significant main chain damage. Current evaluation methods primarily rely on subjective indicators (curlness, feel) or single disulfide bond indicators, lacking a quantitative and objective standard centered on the integrity of the peptide bond main chain.

[0004] Therefore, there is a need for a perming product with structural integrity and its preparation method to overcome the long-standing industry prejudice that "perming inevitably leads to irreversible hydrolysis of peptide bonds". Summary of the Invention

[0005] 1. Key Findings This invention reveals that the synergistic effect of a reducing softener at pH 6.0-7.0, a permeation carrier composed of DMI (dimethyl isosorbide) and oleic acid, precise medium-temperature heating (80-90°C), and rapid cooling after heating (to ≤35°C within 120 seconds) can achieve efficient disulfide bond remodeling and obtain lasting curl while minimizing peptide bond hydrolysis, maintaining the amide III band peak intensity at over 90% of that of the homologous untreated control hair. This level cannot be achieved by using low pH or medium-temperature heating alone without the aforementioned synergistic elements (see comparative example data below).

[0006] 2. Definition - "Homologous untreated control hair": refers to the same hair bundle taken from the same subject and the same anatomical region (e.g., the occipital region), evenly divided into two parts. One part is left untreated as a control, while the other part is treated according to this invention; or it can be taken from adjacent equal-length segments of the same hair. The control and treated samples are stored in the same environment (room temperature, dryness, and protection from light), and all Raman tests are completed within 24 hours of sampling to avoid natural changes caused by prolonged storage.

[0007] - "Peptide bond integrity": Raman spectroscopy was used to determine the amide III band (1200-1300 cm⁻¹). -1 Peak intensity, with the phenylalanine cyclic respiration peak (1003 cm⁻¹) as the benchmark. -1 After normalization, the ratio of the treated sample to the control sample is calculated and expressed as a percentage.

[0008] Technical solution: According to one aspect of the present invention, a permed hair product with structural preservation is provided, wherein the permed hair product is human curly hair treated by a perming process, and the amide III band (1200-1300 cm) in the hair keratin is present. -1 Raman peak intensity is based on the phenylalanine cyclic respiration peak (1003 cm⁻¹). -1 After normalization, it is not less than 90% of the homologous untreated control hair; And simultaneously satisfy the following structural characteristics: The coefficient of variation of the radial distribution of disulfide bond Raman signals in the cross-section of a single fiber is less than 15%. The Raman characteristic peak intensity of the outermost 18-methyleicosanoic acid (18-MEA) was not less than 80% of that of the homologous untreated control hair; The DSC curve shows a characteristic endothermic peak of keratin α-helix in the 200-260℃ range, and the absolute value of the change rate of peak temperature and peak area relative to the control is ≤15%. The sulfoalanine content in the hair hydrolysate is less than 0.5 mol / kg.

[0009] According to another aspect of the present invention, a method for preparing the above-described structure-preserving perm product is provided, comprising the following steps: (a) Providing human hair; (b) Apply a softening agent composition with a pH of 6.0-7.0, the softening agent composition comprising a reducing agent and a permeation carrier consisting of dimethyl isosorbide and oleic acid; (c) After cleaning and removing the softener, curl and style the hair with rods; (d) Heat the curled hair at 80-90℃; (e) Within 120 seconds after heating ends, rapidly reduce the hair temperature to ≤35°C; (f) Oxidation and shaping are performed using hydrogen peroxide solution to obtain permed hair products with intact structure.

[0010] According to another aspect of the invention, a softening agent composition for perming is provided, having a pH of 6.0-7.0, comprising a reducing agent and a penetrating carrier composed of dimethyl isosorbide and oleic acid.

[0011] Preferably, in step (b), the softening agent composition is applied to the hair for 10-30 minutes.

[0012] Preferably, in step (d), the heating treatment temperature is 83-87°C and the heating treatment time is 5-12 minutes.

[0013] Preferably, in step (e), the cooling time is controlled to be 60-90 seconds.

[0014] Preferably, in step (f), the concentration of the hydrogen peroxide solution is 2-4 wt%, the pH value of the solution is 3.0-4.0, and the setting time at room temperature is 5-15 minutes.

[0015] Preferably, in the softener composition, the reducing agent is selected from at least one of thioglycolic acid, cysteine, and ammonium thioglycolic acid, and the total concentration is 5-15 wt%.

[0016] Preferably, in the softener composition, the mass ratio of dimethyl isosorbide to oleic acid is 1:0.5-1:2, and the total content of the permeation carrier is 1-10 wt%.

[0017] Preferably, the curl retention rate of the permed hair product is not less than 80% after 30 washes.

[0018] Beneficial effects: This invention is the first to use peptide bond backbone integrity as the core quantitative indicator, achieving ≥90% retention, while also featuring uniform disulfide bond crosslinking (radial CV<15%), surface lipid retention (18-MEA≥80%), no significant thermal denaturation (DSC change≤15%), low oxidative damage (sulfoalanine<0.5 mol / kg), and excellent curl retention (≥80% retention rate after 30 washes), overcoming the industry's technical prejudice that "perming inevitably damages the protein backbone".

[0019] The mechanism is that DMI+ oleic acid carrier can effectively penetrate the cuticle under near-neutral conditions, avoiding the hydrolytic catalysis of peptide bonds by strong bases; rapid cooling after heating locks in the natural conformation of the α-helix, avoiding thermal denaturation caused by high temperature in traditional processes. Attached Figure Description

[0020] Figure 1 Raman spectra comparison diagrams (amide III band region, normalized to 1003 cm⁻¹) of the homologous untreated control, comparative example, and Example 1 of the present invention. -1 Peak); the horizontal axis represents wavenumber (cm). -1 The vertical axis represents the normalized peak intensity.

[0021] Figure 2The image shows the radial distribution curve of disulfide bond Raman signal in a cross-section of a single hair of the present invention; A is a comparative example of traditional perming, with a gradient distribution of disulfide bond signal that is weak on the outside and strong on the inside; B is Example 1 of the present invention, with a uniform and flat distribution of disulfide bonds; the horizontal axis is the distance from the epidermis (μm), and the vertical axis is the normalized intensity.

[0022] Figure 3 The above is a comparison diagram of the DSC heat flow curves of the present invention (α-spiral denaturation endothermic peak region); A is the untreated control from the same source, B is the conventional perming control (no α-spiral endothermic peak), and C is Example 1 of the present invention, with the peak shape completely consistent with the control; the horizontal axis is temperature (°C), and the vertical axis is heat flow (MW).

[0023] Figure 4 This is a graph showing the change in curl retention rate as a function of the number of washes according to the present invention; the horizontal axis represents the number of washes, and the vertical axis represents the curl retention rate.

[0024] Figure 5 This is a flowchart of the preparation method of the present invention. Detailed Implementation

[0025] To make the technical solution of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] (The following testing methods are only used to characterize the technical effects of the product of this invention and do not constitute a limitation on the scope of protection of this invention.) I. Standardized Testing Methods Raman spectroscopy detection: The instrument used a confocal Raman microscope (Renishaw in Via), a 785 nm laser, a 50× objective lens, and a laser power ≤10 mW; the spectral acquisition range was 800-1800 cm⁻¹. -1 Integration time 10 s, cumulative scans 3 times; baseline corrected using polynomial fitting, all peak intensities at 1003 cm⁻¹ -1 Normalization of the phenylalanine peak.

[0027] Cross-sectional radial distribution detection of disulfide bonds: Hair was embedded in OCT cryosections, with a section thickness of 10 μm; samples were collected at 500-550 cm intervals along the cross-sectional radius from the outer layer of the cuticle to the center of the cortex, at intervals of 1-2 μm. -1 Disulfide bond signal; calculate the mean and standard deviation of the intensity of all sampling points, and the coefficient of variation CV = (standard deviation / mean) × 100%.

[0028] Differential scanning calorimetry (DSC): The sample was equilibrated in an environment with 50% relative humidity for 24 h; in a nitrogen atmosphere, the heating rate was 10℃ / min, and the scanning range was 30-300℃; the peak temperature Tm and peak area ΔH of keratin α-helix denaturation were recorded at 200-260℃; the rate of change of the index was calculated as |(control value - sample value) / control value|×100%.

[0029] 18-MEA surface lipid detection: Raman spectroscopy was used to detect 1100 cm⁻¹ -1 Nearby characteristic peak intensities (normalized to 1003 cm⁻¹) -1 (This can be supplemented by XPS detection of sulfur content on the hair surface as an auxiliary reference indicator of the integrity of the surface lipid layer.)

[0030] Detection of sulfoalanine content: Hair samples were hydrolyzed with 6 M HCl at 110℃ for 24 h; quantitative analysis was performed using HPLC combined with pre-column derivatization of o-phthalaldehyde, with units of mol / kg hair.

[0031] Curl persistence test: The hair strands were washed with a 0.5% sodium lauryl sulfate solution at 40°C for 5 minutes, followed by rinsing with water for 1 minute. After every 5 washes, the natural hanging length of the hair strands was measured under 50% standard humidity.

[0032] Formula for calculating curl retention rate: Retention rate = (L0 - L) n ) / (L0-L_c)×100%; L0: Initial straightening length of the hair strand; L n : Hanging length after n washes; L_c: Shortest length after complete curling; Each sample was measured 3 times and the average value was taken.

[0033] II. Comparative Example: Traditional High-Alkali High-Temperature Perming Experimental materials: Homologous hair bundles in the occipital region of healthy Asians, divided into 5 parts, with 1 part serving as a blank control.

[0034] Process parameters: softener pH=9.5, ammonium thioglycolate 12%, apply at room temperature for 15 min; heat at 110℃ for 10 min; cool naturally at room temperature for >5 min; oxidative setting uses 3 wt% hydrogen peroxide (pH 3.5), at room temperature for 10 min.

[0035] The sample size was n=6. Two hair strands were taken from each hair bundle, and three points were tested on each hair strand. The data are the mean ± standard deviation.

[0036]

[0037] Experimental conclusion: Traditional perming does not meet the structural preservation standards of this invention in any of its indicators.

[0038] III. Example 1 (Healthy Hair, Preferred Solution) Experimental materials: Hair strands from healthy Asians of the same origin as the control group, with a separate sample reserved as a blank control.

[0039] Softener composition: pH=6.5, ammonium thioglycolate 10 wt%, DMI 3 wt% + oleic acid 3 wt%, the remaining components are aqueous matrix; apply at room temperature and allow to act for 20 min.

[0040] Hot working: Heating at 85℃ (±1℃) for 8 minutes.

[0041] Rapid cooling: Immediately after heating ends, a semiconductor refrigeration device is used for forced cooling, and the hair temperature drops to ≤35℃ within 75 seconds; it can be replaced by other forced cooling equipment such as cold air circulation, pre-cooled metal cold compress, and temperature control clamps.

[0042] Oxidative fixation: 3 wt% hydrogen peroxide solution (pH=3.5), stand at room temperature for 10 min; rinse thoroughly, then partially dry and blow dry, and allow to air dry completely at room temperature.

[0043] The sample size was n=6, and the test results are as follows:

[0044] Experimental conclusion: The integrity of peptide bonds in hair strands reached 96%, fully meeting the standards of this invention; compared with traditional perming, all indicators showed statistically significant differences (p<0.01).

[0045] IV. Example 2 (pH boundary verification) The softener pH=6.0, the heating temperature is 82℃, and the other raw materials and process parameters are completely consistent with those in Example 1.

[0046] Test results: Amide III band 92%±4%, disulfide bond CV 11%±3%, 18-MEA retention 82%±5%, sulfoalanine 0.20±0.1 mol / kg, absolute change of DSC index ≤10%, curl retention rate after 10 washes 88%±3%.

[0047] V. Example 3 (pH boundary verification) The softener has a pH of 6.8 and a heating temperature of 88°C. The other raw materials and process parameters are completely consistent with those in Example 1.

[0048] Test results: Amide III band 94%±3%, disulfide bond CV 9%±3%, 18-MEA retention 85%±4%, sulfoalanine 0.15±0.05 mol / kg, absolute change of DSC index ≤8%, curl retention rate after 10 washes 90%±2%.

[0049] Experimental conclusions: All indicators of Examples 2 and 3 meet the standards of the present invention for structure-preserving permed hair products, and the process range has good tolerance.

[0050] VI. Comparative Example 1 (DMI + oleic acid osmotic carrier omitted) The softener pH was 6.5 (same as in Example 1), the formulation did not contain DMI or oleic acid, and the rest of the process and raw materials were completely consistent with Example 1; the sample size n=6.

[0051] Test results: Amide III band 78%±4%, disulfide bond CV 22%±5%, 18-MEA retention 52%±6%, sulfoalanine 0.55±0.1 mol / kg, DSC peak area change -18%±3%, curl retention rate after 10 washes 84%±3%; all indicators were significantly worse than those in Example 1 (p<0.01).

[0052] VII. Compare with Example 2 (eliminate rapid cooling, use natural cooling) The softener formulation is the same as in Example 1. After heating to 85°C, the temperature is naturally cooled to room temperature for about 8 minutes until it drops to 35°C. The rest of the process remains unchanged. The sample size is n=6.

[0053] Test results: Amide III band 83%±4%, disulfide bond CV 18%±4%, 18-MEA retention 70%±5%, sulfoalanine 0.45±0.1 mol / kg, DSC peak area change -16%±4%, curl retention rate after 10 washes 81%±3%; the indicators were significantly lower than those in Example 1.

[0054] Experimental conclusion: Permeation carrier and rapid cooling after heating are essential components for synergy; the absence of either one will prevent the achievement of peptide bond integrity ≥90%.

[0055] 8. Example 4 (Compatibility Verification for Bleached Damaged Hair) Experimental materials: Moderately damaged Asian hair bleached once (original healthy hair bleached with 6 wt% hydrogen peroxide for 30 min; bleaching only damaged pigment, and the baseline peptide bond integrity was not significantly different from that of healthy hair); all materials and processes from Example 1 were reused. Sample size n=6, and the test results are as follows:

[0056] Experimental conclusions: For bleached damaged hair, peptide bond integrity can still reach over 91%, and disulfide bond uniformity, thermal stability, and curl retention all meet the core standards of this invention. The 18-MEA retention rate is 72±5%. Considering that the bleaching pretreatment itself leads to some loss of surface lipids, this retention rate is lower than the preferred threshold of 80% for healthy hair, which is an expected result. However, compared with a homologous bleached but unpermed control, the 18-MEA preservation effect of this invention on damaged hair is still significantly better than that of traditional perming processes (when traditional perming treats bleached hair, 18-MEA usually drops to extremely low levels), indicating that this invention also has a significant structural preservation advantage for damaged hair.

[0057] IX. Summary Table of All Sample Effect Data

[0058] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A perm product that preserves structural integrity, characterized in that, The perming product is human curly hair treated with a perming process, containing amide III bands (1200-1300 cm) in the keratin of the hair strand. -1 Raman peak intensity is based on the phenylalanine cyclic respiration peak (1003 cm⁻¹). -1 After normalization, it is not less than 90% of the homologous untreated control hair; And simultaneously satisfy the following structural characteristics: The coefficient of variation of the radial distribution of disulfide bond Raman signals in the cross-section of a single fiber is less than 15%. The Raman characteristic peak intensity of the outermost 18-methyleicosanoic acid was no less than 80% of that of the homologous untreated control hair; The DSC curve shows a characteristic endothermic peak of keratin α-helix in the 200-260℃ range, and the absolute value of the change rate of peak temperature and peak area relative to the control is ≤15%. The sulfoalanine content in the hair hydrolysate is less than 0.5 mol / kg.

2. A method for preparing the structure-preserving perm product as described in claim 1, characterized in that, Includes the following steps: (a) Providing human hair; (b) Apply a softening agent composition with a pH of 6.0-7.0, the softening agent composition comprising a reducing agent and a permeation carrier consisting of dimethyl isosorbide and oleic acid; (c) After cleaning and removing the softener, curl and style the hair with rods; (d) Heat the curled hair at 80-90℃; (e) Within 120 seconds after heating ends, rapidly reduce the hair temperature to ≤35°C; (f) Oxidation and shaping are performed using hydrogen peroxide solution to obtain permed hair products with intact structure.

3. The preparation method according to claim 2, characterized in that, In step (b), the softening agent composition is applied to the hair for 10-30 minutes.

4. The preparation method according to claim 2, characterized in that, In step (d), the heating treatment temperature is 83-87℃ and the heating treatment time is 5-12 minutes.

5. The preparation method according to claim 2, characterized in that, In step (e), the cooling time is controlled between 60 and 90 seconds.

6. The preparation method according to claim 2, characterized in that, In step (f), the concentration of the hydrogen peroxide solution is 2-4 wt%, the pH value of the solution is 3.0-4.0, and the setting time at room temperature is 5-15 minutes.

7. The preparation method according to claim 2, characterized in that, In the softener composition, the reducing agent is selected from at least one of thioglycolic acid, cysteine, and ammonium thioglycolic acid, with a total concentration of 5-15 wt%.

8. The preparation method according to claim 2, characterized in that, In the softener composition, the mass ratio of dimethyl isosorbide to oleic acid is 1:0.5-1:2, and the total content of the permeation carrier is 1-10 wt%.

9. The structure-preserving perm product according to claim 1, characterized in that, The permed hair products retain at least 80% of their curl after 30 washes.

10. A softening agent composition for perming hair, characterized in that, The softener composition has a pH of 6.0-7.0 and contains a reducing agent and a permeation carrier composed of dimethyl isosorbide and oleic acid.

11. The softener composition according to claim 10, characterized in that, The reducing agent is selected from at least one of thioglycolic acid, cysteine, and ammonium thioglycolic acid, with a total concentration of 5-15 wt%.

12. The softener composition according to claim 10, characterized in that, The mass ratio of dimethyl isosorbide to oleic acid is 1:0.5-1:2, and the total content of the permeation carrier is 1-10 wt%.

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