JPH0695093B2 - Blood stain collection method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bloodstain collecting method for adhering and collecting bloodstains such as fingerprints and footprints on an object at an inspection site.

[0002]

2. Description of the Related Art In current criminal investigations in Japan, the evidence-first principle is adopted, and even if the confession of the suspect or securing of proof of the situation is secured, it cannot be prosecuted without any physical evidence. is the current situation. Further, in the Japanese judicial system, prolongation of trials is unavoidable, and thus secured physical evidence must be kept in its state for a long time.

The fingerprints left at the crime scene in the physical evidence can be strong evidence for identifying the criminal and proving the crime, but in general, an unspecified number of fingerprints are attached near the scene. In many cases, it is extremely difficult to selectively find out the fingerprint of a specific suspect among them, which requires enormous amount of time and labor. Even if the suspect's fingerprint can be found, it may be difficult to prove that he was present or involved in the crime at the time of the crime.

On the other hand, if a blood stain due to a fingerprint formed by the victim's blood is found at the crime scene, it will be an absolute proof to prove that the person with the fingerprint was at the crime scene. If a similar fingerprint is found on a weapon, it is proof that it was involved in the crime. The same thing can be said for blood marks due to footprints.

When such fingerprints or blood marks of footprints are found, they are taken as evidence by taking a photograph. When the blood marks have, for example, a color tone similar to that of the blood marks or adhere to a dark-colored object. Therefore, it becomes extremely difficult to identify blood stains by photographs. In addition, there may be a case where it is practically impossible to take a photograph due to a small space or the like. In such a case, a method is used in which the bloodstains are once transferred to a white material that can be easily identified, and the pictures are taken. In this case, the same image as the actual image can be obtained by printing by inverting the negative of the photograph. Conventionally, gypsum, paper clay, or the like has been used to collect such adhered blood marks by transfer.

[0006]

Various problems have been pointed out in the conventional method using gypsum or paper clay, and it is strongly desired from the forensic site to develop a new method in place of them. The conventional method of using gypsum is to put a mud substance that is a mixture of gypsum and water on an object with blood stains, and peel off the gypsum from the object after hardening. Blood stains are transferred to the plaster side.
This method is to soften the blood coagulated by the water contained in the gypsum mud and peel it off from the object, but if the water in the gypsum mud is too much, the blood coagulated due to the water is dissolved and fingerprints etc. There is a risk that the pattern will be blurred and will not be identifiable. If the water content in the gypsum mud is too low, the coagulated blood will not be sufficiently softened and the blood stains will not be separated.

In such a method using gypsum, the ratio of gypsum and water must be strictly controlled,
Requires a high degree of skill in operation. The method using gypsum is easy to apply on a horizontal surface, but it is extremely difficult to apply it on a vertical surface or a ceiling. Furthermore, when plaster is used, there is a problem that mold grows during storage, and there is a problem in keeping evidence for a long time. Furthermore, due to the brittleness peculiar to gypsum, more than necessary thickness is required, resulting in bulkiness,
It is necessary to consider a storage location that can withstand heavy objects. In addition, when collecting blood stains, a blood stain detection liquid (tetramethylbenzidine + hydrogen peroxide solution) may be applied in order to make the pattern of blood clearer, but when gypsum is used, the pattern becomes blurred, No clear pattern can be obtained.

On the other hand, the method of using paper clay is to press the paper clay directly onto the blood stain attached to the object and transfer the blood stain to the paper clay side. In this case as well, blood stains coagulated by a small amount of water contained in paper clay are softened and collected. However, with this method, the degree of softening of blood stains differs depending on the amount of residual water in the paper clay, so that considerable skill is required for the operation, and reliable collection cannot be expected. Further, since paper clay is soft, the pattern will be deformed if care is not taken in handling during or after collecting blood stains, and there is a problem in long-term storage.

In view of the above points, the present invention can collect bloodstains quickly and reliably, and can use a bloodstain detection liquid such as tetramethylbenzidine, which is strong, does not deform, and is lightweight and can be stored for a long period of time. An object of the present invention is to provide a simple blood stain collection method.

[0010]

In order to solve the above-mentioned problems, the blood-stain collecting method of the present invention uses two kinds of compositions having different forms, that is, a first composition and a second composition, and adheres them to an object. First, the first composition is thinly applied to the bloodstain part, and then the second composition is coated on the first composition and polymerized and cured. Then, the bloodstain is separated from the object and the bloodstain attached to the object is first composition. It is to be adhered to and transferred to the side of the integrally polymerized cured product of the second composition.

The first composition is preferably a one-part composition containing as a main component a monomer having two or more radically polymerizable acrylic or methacrylic groups in the molecule. It is desirable that the first composition has no or extremely low solubility in coagulated blood, and has no or very low compatibility with the release agent.

Further, the first composition undergoes radical polymerization curing at approximately the same time as or before the polymerization curing of the second composition when the second composition is coated on the thinly applied first composition, It is better to form a film.

The second composition used in the present invention is a liquid agent comprising a radically polymerizable methacrylic acid ester, a releasing agent and a tertiary amine, a methacrylic acid ester polymer or copolymer, an organic peroxide. It is desirable that the radical polymerization takes place at room temperature to cure by mixing the powder and the liquid at the time of use. Further, when the powder liquid mixture is mixed in the range of 0.4 to 0.8 parts by weight with respect to 1 part by weight of the powder agent, the state is changed from the slurry state at the time of the mixing to the sticky state, and then polymerized and cured. Is preferred.

[0014]

A releasing agent is contained in the second composition used in the present invention for the purpose of inhibiting the adhesiveness between the object and the second composition, that is, imparting the releasing property to the object. Originally, methacrylic acid ester is used as an adhesive and has a strong adhesive action to many objects. When such a strong adhesiveness is used in the present invention, the adhesiveness to blood stain becomes good, which is preferable from the viewpoint of blood stain collection, but the polymerized and hardened material does not peel off from the object, resulting in blood stain collection. The purpose cannot be achieved.

In order to improve such a problem, in the present invention, a releasing agent having a large external releasing action on an object is added to the second composition. As a result, the adhesiveness to the object is significantly reduced, and the phenomenon that the cured product does not separate from the object can be avoided. However, from the viewpoint of collecting blood stains, the releasing action of the material is a major obstacle. That is, when blood stains are collected with only the second composition, the release agent in the composition wets the surface of the blood stains, and significantly impairs the adhesiveness between the blood stains and the second composition. Therefore, it becomes difficult to collect a bloodstain with only the second composition.

Therefore, in the present invention, the method of applying the first composition thinly on the bloodstain is applied prior to the coating with the second composition. Since the first composition has no or very low solubility in coagulated blood, the bloodstain pattern does not bleed when applied with a brush or the like. Since the first composition has no compatibility or is extremely incompatible with the release agent, it can be prevented from being wetted by the release agent by pre-application on the surface of the blood stain. Therefore, the first composition and the blood mark are strongly adhered to each other, and the blood mark attached to the object can be surely transferred to the first composition side.

This first composition is not self-curing,
By coating the thinly coated film with the second composition, the tertiary amine (polymerization accelerator) and the organic peroxide (polymerization initiator) contained in the second composition can rapidly react (second (Approximately as fast as the composition cures or faster)
Hardens. Therefore, when the coated second composition is peeled off from the object at the time of curing, the first composition and the second composition are both cured and integrated, and the adhesive strength between the first composition and the object is higher than the adhesive strength between the first composition and the object. The adhesive strength due to the chemical reaction between the first composition and the second composition is higher, and the first composition can be separated from the object together with the bloodstains and collected.

The second composition is a powder-liquid mixed type, and the state of the second composition changes from a slurry state to a sticky state after mixing, so that the method of use can be appropriately changed depending on the situation. For example, when collecting blood stains on a horizontal surface, a slurry-like material may be used by flowing, and when collecting blood stains on a vertical surface or a ceiling, a mochi-like material should be pressed. Good.

[0019]

EXAMPLE Two types of compositions, a first composition and a second composition, are used in the blood stain collection method of the present invention. There are various types of monomers having two or more radically polymerizable acrylic groups or methacrylic groups in the molecule, which compose the first composition. Among them, those that dissolve coagulated blood and liquid paraffin are included. Those that are compatible with are excluded. Specific examples of the monomer that can be used in the present invention include polyethylene glycol dimethacrylate represented by the general formula of Chemical Formula 1 below.

[0020]

[Chemical 1]

Here, n = 1 to 10, R ₁ and R ₂ are hydrogen or a methyl group, and the monomers shown in Chemical formula 2, Chemical formula 3, Chemical formula 4 and Chemical formula 5 below can also be used.

[0022]

[Chemical 2]

[0023]

[Chemical 3]

[0024]

[Chemical 4]

[0025]

[Chemical 5]

Here, m, n = 0 to 3, R ₁ , R ₂ ,
R ₃ and R ₄ are hydrogen or a methyl group. The above-mentioned monomers include various ones from low viscosity to high viscosity, and some of them have too high a viscosity and cannot be put to practical use. is there. In that case, it may be appropriately diluted with a low-viscosity monomer. In the above-mentioned polyethylene glycol dimethacrylate, n =
Those having a viscosity of 1 to 3 have a considerably low viscosity and are therefore effective as diluents. In addition to the polyethylene glycol dimethacrylate described above, radical-polymerizable monomethacrylate can be applied, but generally, these have good compatibility with the release agent, so use of a large amount must be avoided. On the other hand, among the monomethacrylates, those having an alcoholic hydroxyl group in the molecule such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, etc. have extremely poor compatibility with the release agent, and are therefore used as diluents for this purpose. Is suitable.

The monomer having two or more radically polymerizable acryl groups or methacryl groups in the molecule, which constitutes the first composition, is a tertiary amine contained in the second composition when contacted with the second composition, It is not necessary to add a tertiary amine or a catalyst of an organic peroxide in the first composition, because polymerization and curing can be achieved by the action of the organic peroxide. However, the curing rate may be very slow depending on the monomer used, and in such a case, the catalyst described above may be added to the monomer. In this case, the addition of organic peroxide is
It is preferable to add a tertiary amine because it causes a problem in storage stability of the composition. Tertiary amines that can be used for this purpose include N.I. N'-dimethylaniline, N, N '
-Diethylaniline, N, N'-dimethylparatoluidine, N, N'-diethylparatoluidine and the like are included.

The second composition used in the present invention comprises two components, a liquid agent and a powder agent, and both components are mixed at the time of use.
The liquid agent, which is a constituent component of the second composition, contains a methacrylic acid radical-polymerizable ester, a release agent, and a tertiary amine as main components. The radical-polymerizable methacrylic acid ester preferably has 4 or less carbon atoms in the ester residue, and examples thereof include methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, and methacrylic acid. Isobutyl acid, 2-hydroxyethyl methacrylate, etc. are included, and the use of methyl methacrylate is particularly preferable. These methacrylic acid esters may be used alone or in combination of two or more. The reason why the number of carbon atoms in the ester residue is 4 or less is that the reactivity is remarkably lowered when the number of carbon atoms is larger than that.

Next, as the release agent that can be used in the liquid composition of the second composition, any release agent can be used as long as it has excellent compatibility with the methacrylic acid ester and does not inhibit the polymerization reaction of the methacrylic acid ester. However, liquid paraffin, silicone oil, fatty acid ester and the like are preferable, and liquid paraffin is most suitable for this purpose.
These release agents are used as the methacrylic ester 10.
It is preferable to add 1 to 20 parts by weight to 0 parts by weight. Here, the amount of the release agent added is set to 1 to 20 parts by weight because when the amount is less than 1 part by weight, a sufficient releasing effect cannot be obtained, and when the amount is more than 20 parts by weight, the radicals after powder liquid mixing are This is because the polymerization reaction is suppressed and an excessive amount of the releasing agent is separated in a large amount.

Further, as the tertiary amine which can be used in the liquid agent of the second composition, N, N'-dimethylaniline, N,
N'-diethylaniline, N, N'-dimethylparatoluidine, N, N'-diethylparatoluidine, N, N '
-Diethyl-metatoluidine, N, N'-di (β-hydroxyethyl) paratoluidine and the like can be mentioned. The addition amount of these varies depending on the type of methacrylic acid ester used and the type and addition amount of organic peroxide in the powder to be described later, but is set to 0.1 to 5 parts by weight per 100 parts by weight of methacrylic acid ester. Preferably. Here, the setting range is set to 0.1 to 5 parts by weight when the amount is less than 0.1 parts by weight, the catalytic effect of the tertiary amine cannot be sufficiently obtained, and when it is more than 5 parts by weight, the addition amount is This is because the effect of increasing the number remarkably decreases.

On the other hand, the powder which is another constituent of the second composition used in the present invention is mainly composed of a methacrylic acid ester polymer or copolymer and an organic peroxide. The ester polymer or copolymer preferably has 4 or less carbon atoms in the ester residue, and examples thereof include polymethylmethacrylate, polyethylmethacrylate, polypropylmethacrylate and polybutylmethacrylate. And homopolymers such as methyl methacrylate / ethyl methacrylate copolymer, methyl methacrylate / propyl methacrylate copolymer, methyl methacrylate / butyl methacrylate copolymer and the like. These polymers or copolymers may be used alone or in a blend of two or more kinds. These may have various molecular weights and particle sizes, but have a molecular weight of 100,000 to 1,000,000 and a particle size of 10 μ to 100.
The range of μ is preferable.

The powder of the second composition used in the present invention contains an organic peroxide as a polymerization initiator. Examples of the organic peroxide include diacyl peroxide such as benzoyl peroxide. . When benzoyl peroxide is used, its addition amount is 0.1% based on 100 parts by weight of the methacrylic acid ester polymer or copolymer.
It is preferably 1 to 5.0 parts by weight. Here, if the addition amount is less than 0.1 parts by weight, a practical curing rate cannot be obtained, and if it is more than 5.0 parts by weight, the effect of increasing the addition amount cannot be sufficiently obtained. Alumina,
Inorganic fillers such as silica, calcium carbonate and talc, and pigments such as titanium dioxide may be added.

The second composition used in the present invention is used by mixing 1 part by weight of the powder agent with 0.3 to 1.0 part by weight of the liquid agent. When the amount of the liquid agent added is less than 0.3 parts by weight, the mixing property of the powder liquid becomes extremely poor, and a homogeneous mixture cannot be obtained. On the other hand, if the amount of the liquid agent added is more than 1.0 part by weight, the viscosity of the powder / liquid mixture becomes too low, and the polymerization / curing time is significantly delayed.

(Experimental example 1) Preparation of first composition 2.2 5-bis [4- (3-methacryloxy-2-hydroxypropoxyphenyl] propane 50.0 parts by weight, triethylene glycol dimethacrylate 40.0 parts by weight Then, 10.0 parts by weight of 2-hydroxyethyl methacrylate and 0.2 parts by weight of N, N'-dimethylparatoluidine were placed in a beaker and stirred for 1 hour to obtain a uniform liquid substance.

Preparation of liquid preparation of the second composition 75.0 parts by weight of methyl methacrylate, liquid paraffin 1
5.0 parts by weight, 10.0 parts by weight of isobutyl methacrylate, and 1.0 parts by weight of N, N'-dimethylparatoluidine were placed in a beaker and mixed with stirring for 10 minutes to prepare a liquid agent.

Preparation of Dust of Second Composition 40.0 parts by weight of polymethylmethacrylate having an average molecular weight of 300,000 and an average particle diameter of 60 μ, methyl methacrylate / ethyl methacrylate copolymer having an average molecular weight of 500,000 and an average particle diameter of 50 μ Combined (methyl methacrylate / ethyl methacrylate molar ratio = 3/2) 30.0 parts by weight, 10.0 parts of polyethyl methacrylate having an average molecular weight of 200,000 and an average particle weight of 50 μ,
20.0 parts of calcium carbonate and 1.0 part of benzoyl peroxide were placed in a ball mill and mixed for 1 hour to prepare a powder.

(Experimental Results) 1 Curing Time of the First Composition (Room Temperature 23 ° C.) A thin film of the second composition was coated with a thin coating of the first composition on the polyvinylidene chloride film with a brush for 2 minutes. And 1.2 g of the solution. The film was gradually peeled off at regular intervals, and the time required for the first composition to cure was determined. As a result, the film was cured 3 minutes after coating.

2 State change of the second composition (room temperature 23 ° C.) When 2 g of the powdered agent and 1.2 g of the liquid agent are mixed, good fluidity is exhibited for about 1 minute from the start of mixing, and then about 1 minute later. The rice cake became sticky and was kept for about 5 minutes.

(3) Curing time of the second composition (room temperature: 23 ° C.) A thermocouple was inserted into a sample prepared by mixing 2 g of the powder agent and 1.2 g of the liquid agent, and the curing time was calculated from the exothermic peak.
It was 15 seconds.

4 Peelability and Blood Stain Collectability Human blood was thinly applied to P-tile, corrugated cardboard, glass, stainless steel plate and concrete surface, and left for 24 hours. The first composition was thinly applied with a brush on the coagulated blood stain. Next, 10 g of the powder and 6 g of the liquid are mixed, and 2
After being left for a minute, the rice cake was pressed against the above-mentioned bloodstain so as to cover it much wider than the bloodstain. After 10 minutes, the cured product was peeled off from each object, but in each case, it was easily peeled off by applying a light impact to the end of the cured product. In any case, the blood stain applied to the object was completely transferred to the cured product side.

5 Reaction to Blood Stain Detecting Solution Tetramethylbenzidine was thinly applied to the surface of each of the above-mentioned cured products where blood marks were collected and dried. Next, Japanese paper soaked with hydrogen peroxide was pressed against the tetramethylbenzidine coated surface. As a result, blood stains became clear and identification was easy in both cases.

6 Storability As a result of leaving the cured product in a high temperature and high humidity environment for 6 months, no deterioration of the material was observed and no mold was observed at all.

[0043]

Since the present invention is configured as described above, it has the following effects. The first composition is thinly applied to the bloodstain portion adhered to the object, and the second composition is coated and polymerized and cured on the first composition, and then peeled off from the object to remove the bloodstain adhered to the object from the first composition. It can be adhered and transferred to the side of the mono-polymerized cured product of the second composition, and can collect blood stains quickly and reliably, and a blood stain detection liquid such as tetramethylbenzidine can be used, and it does not deform because it has strength. It is lightweight and can enable long-term storage.

Claims (6)

[Claims] 1. A first composition is thinly applied to a bloodstain portion adhered to an object, and then a second composition is coated on the first composition and polymerized and cured, and then peeled from the object. ,
A bloodstain collecting method, characterized in that the bloodstain attached to an object is adhered to and transferred to the side of the monopolymerization cured product of the first composition and the second composition. 2. The first composition is a one-part composition containing as a main component a monomer having two or more radically polymerizable acrylic groups or methacrylic groups in the molecule. Blood stain collection method. 3. The blood stain collection according to claim 1, wherein the first composition has no or very low solubility in coagulated blood and no or very low compatibility with a release agent. Method. 4. The first composition, when the second composition is coated on the thinly applied first composition, undergoes radical polymerization curing almost simultaneously with or before the polymerization curing of the second composition to form a film. The blood stain collection method according to claim 1, wherein the blood stain is formed. 5. A second composition comprising a liquid agent comprising a radically polymerizable methacrylic acid ester, a release agent and a tertiary amine, and a powder agent comprising a methacrylic acid ester polymer or copolymer and an organic peroxide. The method for collecting blood stains according to claim 1, wherein the method is characterized in that radical polymerization occurs at room temperature to cure by mixing the liquid agent and the powder agent at the time of use. 6. The second composition, when the liquid agent is mixed in the range of 0.3 to 1.0 parts by weight with respect to 1 part by weight of the powder agent, the second composition undergoes polymerization and hardening from a slurry state at the beginning of mixing to a sticky state. The method for collecting blood stains according to claim 1, wherein